Science Advisory Board 

Office of the Administrator

EPA-SAB-09-012 | May 2009 | www.epa.gov/sab

SABValuing the Protection of 

Ecological Systems and Services

A Report of the EPA Science Advisory Board 

i

EPA-SAB-09-012

The Honorable Lisa P. Jackson

Administrator

U.S. Environmental Protection Agency

1200 Pennsylvania Avenue, N.W.

Washington, D.C. 20460

Subject: Valuing the Protection of Ecological Systems and Services: A Report of the EPA Science Advisory Board

Dear Administrator Jackson:

We are pleased to submit the accompanying SAB report on valuing the protection of ecological systems and 

services. There is increasing recognition of the numerous and important services that ecosystems provide to human 

populations, such as flood protection, water purification, and climate control. Protecting ecological systems and 

services is part of EPA’s core mission. To determine the best options for protecting the environment and to demonstrate 

the full value of its actions to Congress and others, EPA must be able to fully and accurately value the ecological effect 

of its actions.

Unfortunately, as the accompanying report discusses, past efforts at EPA to value the Agency’s protection of 

ecological systems and services have often suffered from a number of limitations. They have tended to focus on 

those ecological effects that are easiest to value because of available data or studies, rather than on the full range of 

ecological values that people care about. Where the Agency has valued ecological benefits, it has sometimes used 

outdated studies of benefits in one context to estimate the current benefits of protective measures in quite different 

contexts. In valuing ecological effects, the Agency also has generally drawn on economic methods and has not taken 

advantage of the full range of valuation methods that could be useful. Finally, valuations have often not adequately 

addressed uncertainty.

In an effort to strengthen the scientific basis of Agency decisions affecting ecological systems and services, in 2003 

the SAB created a committee to examine ecological valuation practices, methodologies, and research needs. To ensure 

a broad perspective on this inherently interdisciplinary topic, the SAB appointed experts in decision science, ecology, 

economics, engineering, law, philosophy, political science, and psychology to the committee. The interdisciplinary 

character of the committee’s analysis increased both the complexity of its discussions and the length of time needed to 

complete its study. Value is not a single, simple concept, and disciplines often have different understandings of what 

value is and how it should be measured. The resulting report is well worth the additional time and effort, specifically 

because it brings together these different perspectives. This consensus report represents the first major examination of 

ecological valuation to consider both economic and non-economic methods of valuation. We believe the report makes 

a significant contribution to the literature, while providing practical advice for EPA.

The report recommends that EPA take a number of steps to improve ecological valuation at the Agency. First, EPA 

should focus on valuing all ecological effects that people believe are important, not simply those effects that are easiest 

to value. To do so, EPA should begin each valuation by developing a conceptual model of the relevant ecosystem and 

the ecosystem services that it provides and use that model, along with information about relevant public concerns and 

needs, as a road map to guide the valuation.

Second, EPA should support efforts at the Agency and elsewhere to develop new approaches to measure or predict 

the ecological effects of EPA’s actions in ways that valuation methods can incorporate. In particular, EPA should 

UNITED STATES ENVIRONMETAL PROTECTION AGENCY

WASHINGTON, DC 20460

May 29, 2009

OFFICE OF THE ADMINISTRATOR

SCIENCE ADVISORY BOARD
ii

focus on the development and use of “ecological production functions” that can estimate how effects on the structure 

and function of ecosystems will affect the provision of ecosystem services that are directly relevant and useful to the 

public. Where ecological production functions do not exist, EPA may be able to rely instead on ecological indicators or 

meta-analysis to provide information about the effects of governmental actions on these services.

Third, the Agency should consider the use of a broader suite of valuation methods than it has historically 

employed, so long as the methods meet appropriate validity and related criteria. The report considers the possible use 

of not only economic methods, but also measures of attitudes, preferences, and intentions; civic valuation; decision 

science approaches; ecosystem benefit indicators; biophysical ranking methods; and cost as a proxy for value. EPA 

could usefully employ some of these methods in identifying services of importance to the public (as recommended 

above), providing information about multiple sources and concepts of value, and better capturing the full range of 

contributions stemming from ecosystem protection. EPA can also improve its ecological valuations by carefully 

evaluating and overseeing its transfer of value information from one site to another and by more fully characterizing 

and communicating uncertainty. Because uncertainty will always exist, the mere existence of uncertainty should not be 

an excuse for delaying action, but the Agency should ensure that uncertainty is carefully analyzed and communicated 

in any valuation that EPA performs.

EPA should consider making greater use of ecological valuation in a variety of contexts and throughout the Agency. 

For this reason, the report discusses how the above recommendations can be implemented in three different contexts: 

national rule making, regional partnerships, and site-specific decisions. To date, the focus of ecological valuations at 

EPA has been national rule makings. However, as described in the accompanying report, EPA regional offices may 

also find valuation useful in setting priorities, such as targeting projects for wetland restoration and enhancement, or 

in identifying critical ecosystems or ecological resources for attention. Valuation may also be useful to EPA in making 

decisions about the remediation, restoration, and redevelopment of contaminated land or other sites. In addition, 

EPA may want to use valuations to assist state and local governments, other federal agencies, and non-governmental 

organizations in deciding how best to protect lands and resources and in communicating the suitability of particular 

management approaches. Because valuations in these additional settings are generally subject to fewer legal directives 

or restrictions than valuations conducted for national rule makings, they may be a particularly appropriate setting in 

which to test and evaluate the use of a wider range of valuation methods. 

Finally, the report provides recommendations for how EPA’s research program can help provide the ecological 

information needed for valuation, develop and test valuation methods, and share data. A number of these 

recommendations reinforce the research plans already developed by the Office of Research and Development and 

other Agency groups.

The SAB thanks EPA staff in both program and regional offices for their help in the work of the committee and 

applauds the efforts that the Agency is already taking to improve its ecological valuations. As part of its work, the 

committee provided an advisory (EPA-SAB-ADV-05-004) for the drafting of EPA’s Ecological Benefits Assessment 

Strategic Plan, which previewed many of the recommendations in the accompanying report. 

We appreciate the opportunity to provide advice on this very important topic, and we look forward to receiving 

your response. The SAB would be pleased to assist EPA in implementing the report’s recommendations, if the Agency 

would find the support valuable.

 Sincerely,

/Signed/

Dr. Deborah L. Swackhamer

Chair 

Science Advisory Board

/Signed/

Dr. Barton H. Thompson, Jr.

Chair

SAB Committee on Valuing the 

Protection of Ecological Systems 

and Services

/Signed/

Dr. Kathleen Segerson

Vice-Chair 

SAB Committee on Valuing the 

Protection of Ecological Systems 

and Services
iii

CHAIR

Dr. Barton H. (Buzz) Thompson, Jr., Robert E. Paradise Professor of Natural Resources Law at the Stanford Law 

School and Perry L. McCarty, Director, Woods Institute for the Environment, Stanford University, Stanford, CA

VICE-CHAIR

Dr. Kathleen Segerson, Professor, Department of Economics, University of Connecticut, Storrs, CT

MEMBERS

Dr. William Louis Ascher, Donald C. McKenna Professor of Government and Economics, Claremont McKenna 

College, Claremont, CA

Dr. Gregory Biddinger, Coordinator, Natural Land Management Programs, Toxicology and Environmental Sciences, 

ExxonMobil Biomedical Sciences, Inc., Houston, TX

Dr. Ann Bostrom, Associate Dean of Research and Associate Professor, Daniel J. Evans School of Public Affairs, 

University of Washington, Seattle, WA

Dr. James Boyd, Senior Fellow, Director, Energy & Natural Resources Division, Resources for the Future, 

Washington, DC

Dr. Robert Costanza, Gordon and Lulie Gund Professor of Ecological Economics and Director, Gund Institute for 

Ecological Economics, Rubenstein School of Environment and Natural Resources, The University of Vermont, 

Burlington, VT

Dr. Terry Daniel, Professor of Psychology and Natural Resources, Department of Psychology, Environmental 

Perception Laboratory, University of Arizona, Tucson, AZ

Dr. A. Myrick Freeman, William D. Shipman Professor of Economics Emeritus, Department of Economics, Bowdoin 

College, Brunswick, ME

Dr. Dennis Grossman, Senior Policy Advisor, International Government Relations, The Nature Conservancy, 

Arlington, VA

Dr. Geoffrey Heal, Paul Garrett Professor of Public Policy and Business Responsibility, Columbia Business School, 

Columbia University, New York, NY

Dr. Robert Huggett, Consultant and Professor Emeritus, College of William and Mary, Williamsburg, VA

Dr. Douglas E. MacLean, Professor, Department of Philosophy, University of North Carolina, Chapel Hill, NC

Dr. Harold Mooney, Paul S. Achilles Professor of Environmental Biology, Department of Biological Sciences, 

Stanford University, Stanford, CA

Dr. Louis F. Pitelka, Professor, Appalachian Laboratory, University of Maryland Center for Environmental Science, 

Frostburg, MD

Dr. Stephen Polasky, Fesler-Lampert Professor of Ecological/Environmental Economics, Department of Applied 

Economics, University of Minnesota, St. Paul, MN

Dr. Paul G. Risser, Chair and Chief Operating Officer, University Research Cabinet, University of Oklahoma, 

Norman, OK 

Dr. Holmes Rolston, University Distinguished Professor, Department of Philosophy, Colorado State University, Fort 

Collins, CO

U.S. Environmental Protection Agency

Science Advisory Board

Committee on Valuing the Protection of Ecological Systems and Services
iv

Dr. Joan Roughgarden, Professor, Biological Sciences and Evolutionary Biology, Stanford University, Stanford, CA

Dr. Mark Sagoff, Senior Research Scholar, Institute for Philosophy and Public Policy, School of Public Affairs, 

University of Maryland, College Park, MD

Dr. Paul Slovic, Professor, Department of Psychology, Decision Research, Eugene, OR

Dr. V. Kerry Smith, W.P. Carey Professor of Economics, Department of Economics, W.P Carey School of Business, 

Arizona State University, Tempe, AZ

CONSULTANTS TO THE COMMITTEE

Dr. Joseph Arvai, Professor, Environmental Science and Policy Program, and Department of Community, Agriculture, 

Resource and Recreation Studies (CARRS), Michigan State University, East Lansing, MI

Dr. Allyson Holbrook, Assistant Professor of Public Administration and Psychology, Survey Research Laboratory, 

University of Illinois at Chicago, Chicago, IL

Dr. Jon Krosnick, Frederic O. Glover Professor in Humanities and Social Sciences, Professor of Communication, 

Director, Methods of Analysis Program in the Social Sciences, Associate Director, Institute for Research in the Social 

Sciences, Stanford University, Palo Alto, CA

SCIENCE ADVISORY BOARD STAFF

Dr. Angela Nugent, Science Advisory Board Staff Office, Washington, DC
v

CHAIR

Dr. Deborah L. Swackhamer, Professor of Environmental Health Sciences and Co-Director Water Resources Center, 

Water Resources Center, University of Minnesota, St. Paul, MN

SAB MEMBERS

Dr. David T. Allen, Professor, Department of Chemical Engineering, University of Texas, Austin, TX

Dr. John Balbus, Chief Health Scientist, Environmental Health Program, Environmental Defense Fund, 

Washington, DC

Dr. Gregory Biddinger, Coordinator, Natural Land Management Programs, Toxicology and Environmental Sciences, 

ExxonMobil Biomedical Sciences, Inc., Houston, TX

Dr. Timothy Buckley, Associate Professor and Chair, Division of Environmental Health Sciences, School of Public 

Health, The Ohio State University, Columbus, OH

Dr. Thomas Burke, Professor, Department of Health Policy and Management, Johns Hopkins Bloomberg School of 

Public Health, Johns Hopkins University, Baltimore, MD

Dr. James Bus, Director of External Technology, Toxicology and Environmental Research and Consulting, The Dow 

Chemical Company, Midland, MI

Dr. Deborah Cory-Slechta, Professor, Department of Environmental Medicine, School of Medicine and Dentistry, 

University of Rochester, Rochester, NY

Dr. Terry Daniel, Professor of Psychology and Natural Resources, Department of Psychology, Environmental 

Perception Laboratory, University of Arizona, Tucson, AZ

Dr. Otto C. Doering III, Professor, Department of Agricultural Economics, Purdue University, W. Lafayette, IN

Dr. David A. Dzombak, Walter J. Blenko Sr. Professor of Environmental Engineering, Department of Civil and 

Environmental Engineering, College of Engineering, Carnegie Mellon University, Pittsburgh, PA

Dr. T. Taylor Eighmy, Assistant Vice President for Research and Director of Strategic Initiatives, Office of the Vice 

President for Research, University of New Hampshire, Durham, NH

Dr. Baruch Fischhoff, Howard Heinz University Professor, Department of Social and Decision Sciences, Department 

of Engineering and Public Policy, Carnegie Mellon University, Pittsburgh, PA

Dr. James Galloway, Professor, Department of Environmental Sciences, University of Virginia, Charlottesville, VA

Dr. John P. Giesy, Professor, Department of Zoology, Michigan State University, East Lansing, MI

Dr. James K. Hammitt, Professor, Center for Risk Analysis, Harvard University, Boston, MA

Dr. Rogene Henderson, Senior Scientist Emeritus, Lovelace Respiratory Research Institute, Albuquerque, NM

Dr. James H. Johnson, Professor and Dean, College of Engineering, Architecture & Computer Sciences, Howard 

University, Washington, DC

Dr. Bernd Kahn, Professor Emeritus and Director, Environmental Radiation Center, Nuclear and Radiological 

Engineering Program, Georgia Institute of Technology, Atlanta, GA

Dr. Agnes Kane, Professor and Chair, Department of Pathology and Laboratory Medicine, Brown University, 

Providence, RI

Dr. Meryl Karol, Professor Emerita, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA

Dr. Catherine Kling, Professor, Department of Economics, Iowa State University, Ames, IA

U.S. Environmental Protection Agency

Science Advisory Board
vi

Dr. George Lambert, Associate Professor of Pediatrics, Director, Center for Childhood Neurotoxicology, Robert Wood 

Johnson Medical School-UMDNJ, Belle Mead, NJ

Dr. Jill Lipoti, Director, Division of Environmental Safety and Health, New Jersey Department of Environmental 

Protection, Trenton, NJ

Dr. Lee D. McMullen, Water Resources Practice Leader, Snyder & Associates, Inc., Ankeny, IA

Dr. Judith L. Meyer, Distinguished Research Professor Emeritus, Odum School of Ecology, University of Georgia, 

Athens, GA

Dr. Jana Milford, Professor, Department of Mechanical Engineering, University of Colorado, Boulder, CO

Dr. Christine Moe, Eugene J. Gangarosa Professor, Hubert Department of Global Health, Rollins School of Public 

Health, Emory University, Atlanta, GA

Dr. M. Granger Morgan, Lord Chair Professor in Engineering, Department of Engineering and Public Policy, Carnegie 

Mellon University, Pittsburgh, PA, Immediate SAB Past Chair

Dr. Duncan Patten, Research Professor, Department of Land Resources and Environmental Sciences, Montana State 

University, Bozeman, MT, USA

Mr. David Rejeski, Director, Foresight and Governance Project, Woodrow Wilson International Center for Scholars, 

Washington, DC

Dr. Stephen M. Roberts, Professor, Department of Physiological Sciences, Director, Center for Environmental and 

Human Toxicology, University of Florida, Gainesville, FL

Dr. Joan B. Rose, Professor and Homer Nowlin Chair for Water Research, Department of Fisheries and Wildlife, 

Michigan State University, East Lansing, MI

Dr. Jonathan M. Samet, Professor and Chair, Department of Epidemiology, Bloomberg School of Public Health, Johns 

Hopkins University, Baltimore, MD

Dr. James Sanders, Director and Professor, Skidaway Institute of Oceanography, Savannah, GA

Dr. Jerald Schnoor, Allen S. Henry Chair Professor, Department of Civil and Environmental Engineering, Co-Director, 

Center for Global and Regional Environmental Research, University of Iowa, Iowa City, IA

Dr. Kathleen Segerson, Professor, Department of Economics, University of Connecticut, Storrs, CT

Dr. Kristin Shrader-Frechette, O’Neil Professor of Philosophy, Department of Biological Sciences and Philosophy 

Department, University of Notre Dame, Notre Dame, IN

Dr. V. Kerry Smith, W.P. Carey Professor of Economics, Department of Economics, W.P Carey School of Business, 

Arizona State University, Tempe, AZ

Dr. Thomas L. Theis, Director, Institute for Environmental Science and Policy, University of Illinois at Chicago, 

Chicago, IL

Dr. Valerie Thomas, Anderson Interface Associate Professor, School of Industrial and Systems Engineering, Georgia 

Institute of Technology, Atlanta, GA

Dr. Barton H. (Buzz) Thompson, Jr., Robert E. Paradise Professor of Natural Resources Law at the Stanford Law 

School and Perry L. McCarty Director, Woods Institute for the Environment Director, Stanford University, 

Stanford, CA

Dr. Robert Twiss, Professor Emeritus, University of California-Berkeley, Ross, CA

Dr. Thomas S. Wallsten, Professor, Department of Psychology, University of Maryland, College Park, MD

Dr. Lauren Zeise, Chief, Reproductive and Cancer Hazard Assessment Branch, Office of Environmental Health Hazard 

Assessment, California Environmental Protection Agency, Oakland, CA

SCIENCE ADVISORY BOARD STAFF

Mr. Thomas Miller, EPA Science Advisory Board Staff Office, Washington, DC
vii

EPA’s Science Advisory Board Committee on Valuing the Protection of Ecological Systems and Services would 

like to acknowledge many individuals who provided their perspectives and insights for the committee’s consideration 

in the development of this report.

Many individuals provided perspectives at public meetings of the committee and to members of the committee’s 

Steering Committee. These individuals included: Mr. Geoffrey Anderson, EPA Office of Policy, Economics, and 

Innovation; Ms. Karen Bandhauer, EPA Region 5; Mr. Devereaux Barnes, EPA Office of Solid Waste and Emergency 

Response; Ms. Jan Baxter, EPA Region 9; Dr. Richard Bernkopf, U.S. Geological Survey; Dr. Lenore BeyerClowe, Openlands Project; Dr. Ned Black, EPA Region 9; Mr. Robert Brenner, EPA Office of Air and Radiation; Dr. 

Thomas Brown, USDA Forest Service; Dr. Randall Bruins, EPA, Office of Research and Development; Mr. David 

Chapman, Stratus Consulting; Mr. James DeMocker, EPA, Office of Air and Radiation; Mr. Richard Durbrow, EPA 

Region 4; Mr. Jesse Elam, Northeast Illinois Planning Commission; Mr. William Eyring, Center for Neighborhood 

Technologies; Ms. Jerri-Anne Garl, EPA Region 5; Ms. Iris Goodman, EPA Office of Research and Development; Dr. 

Robin Gregory, Decision Research, Eugene, Oregon; Dr. Sharon Hayes, EPA, Office of Research and Development; 

Dr. Bruce Herbold, EPA Region 9; Dr. Julie Hewitt, EPA Office of Water; Mr. James Jones, EPA Office of Prevention, 

Pesticides, and Toxic Substances; Dr. Robert E. Lee II, EPA Office of Pollution Prevention and Toxics; Dr. Richard 

Linthurst, EPA Office of Research and Development; Dr. Albert McGartland, EPA Office of Policy, Economics, and 

Innovation; Mr. James Middaugh, City of Portland; Dr. Chris Miller, EPA Office of Water; Mr. Michael Monroe, EPA 

Region 9; Dr. Chris Mulvaney, Chicago Wilderness; Dr. Wayne R. Munns, EPA Office of Research and Development; 

Mr. David S. Nicholas, EPA Office of Solid Waste and Emergency Response; Ms. Gillian Ockner, David Evans and 

Associates, Inc.; Dr. Nicole Owens, EPA Office of Policy, Economics, and Innovation; Dr. Stefano Pagiola, World 

Bank; Ms. Karen Schwinn, EPA Region 9; Dr. Michael Slimak, EPA Office of Research and Development; Dr. 

Matthew Small; EPA Region 9; Mr. David Smith, EPA Region 9; Dr. Ivar Strand, University of Maryland; Ms. Alexis 

Strauss, EPA Region 9; Ms. Patti Lynne Tyler, EPA Region 8; Mr. John Ungvarsky, EPA Region 9; Mr. James Van der 

Kloot, EPA Region 5; Mr. William Wheeler, EPA Office of Research and Development; Ms. Louise Wise, EPA Office 

of Policy, Economics, and Innovation; Dr. T.J. Wyatt, EPA Office of Pesticide Programs; and Mr. Steve Young, EPA 

Office of Environmental Information.

The committee would also like to thank the speakers and participants at the SAB Workshop Science for Valuation 

of EPA’s Ecological Protection Decisions and Programs, December 13-14, 2005: Dr. Mark Bain, Cornell University; 

Mr. Robert Brenner, EPA Office of Air and Radiation; Ms. Kathleen Callahan, EPA Region 2; Dr. Ann Fisher, 

Pennsylvania State University; Dr. George Gray, EPA Office of Research and Development; Dr. Brooke Hecht, Center 

for Humans and Nature; Dr. Bruce Hull, Virginia Institute of Technology; Dr. DeWitt John, Bowdoin College; Dr. 

Robert Johnston, University of Connecticut; Dr. Dennis King, University System of Maryland; Dr. Joseph Meyer, 

University of Wyoming; Mr. Walter V. Reid, Stanford University; Dr. James Salzman, University of North Carolina; 

Dr. Michael Shapiro, EPA Office of Water; Dr. Elizabeth Strange, Stratus Consulting; and Dr. Paul C. West, The 

Nature Conservancy.

The committee especially thanks the experts who provided independent review of the report in draft form. Dr. 

Roger Kasperson, Clark University, Dr. James Opaluch, University of Rhode Island, and Dr. Duncan Patton, Montana 

State University, reviewed a draft in October 2007. Dr. Trudy Ann Cameron, University of Oregon, Dr. Thomas 

Dietz, Michigan State University, Dr. Alan Krupnick, Resources for the Future, and Dr. Mark Schwartz, University 

of California - Davis, reviewed a draft in May 2008. The reviewers provided many constructive comments and 

suggestions, but were not, however, asked to endorse the conclusions or recommendations in the report.

Finally, the chair and vice chair of the committee thank former committee members Dr. Domenico Grasso 

(committee chair 2003-2005) and Dr. Valerie Thomas (committee member 2003-2004), who served on a steering 

group for the committee during its early years.

Acknowledgements
viii

NOTICE

This report has been written as part of the activities of the EPA Science Advisory Board (SAB), a public advisory group 

providing extramural scientific information and advice to the Administrator and other officials of the Environmental Protection 

Agency. The SAB is structured to provide balanced, expert assessment of scientific matters related to problems facing the Agency. 

This report has not been reviewed for approval by the Agency and, hence, the contents of this report do not necessarily represent 

the views and policies of the Environmental Protection Agency, nor of other agencies in the Executive Branch of the Federal government, nor does mention of trade names of commercial products constitute a recommendation for use. Reports of the SAB are 

posted on the EPA Web site at http://www.epa.gov/sab.
ix

Table of Contents

Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2 Conceptual framework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

 2.1 An overview of key concepts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.1.1 The concept of ecosystems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.1.2 The concept of ecosystem services. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.1.3 Concepts of value. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2.1.4 The concept of valuation and different valuation methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

 2.2 Ecological valuation at EPA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2.2.1 Policy contexts at EPA where ecological valuation can be important. . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2.2.2 Institutional and other issues affecting valuation at EPA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

2.2.3 An illustrative example of economic benefit assessment related to ecological protection at EPA. . . . . . . 19

 2.3 An integrated and expanded approach to ecological valuation: key features. . . . . . . . . . . . . . . . . . . . . . . . . . 21

2.3.1 Early consideration of effects that are socially important. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

2.3.2 Predicting ecological responses in value-relevant terms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

2.3.3 Use of a wider range of valuation methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

 2.4 Steps in implementing the proposed approach. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

 2.5 Conclusions and recommendations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

3 Building a foundation for ecological valuation: 

predicting ecological responses in value-relevant terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

 3.1 The road map: a conceptual model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

 3.2 The important role of ecological production functions in implementing the conceptual model. . . . . . . . . . . 30

 3.3 Challenges in implementing ecological production functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

3.3.1 Understanding and modeling the underlying ecology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

3.3.2 Identifying ecosystem services. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

3.3.3 Mapping from ecosystem responses to changes in ecosystem services. . . . . . . . . . . . . . . . . . . . . . . . . . . 35

 3.4 Strategies to provide the ecological science to support valuation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

3.4.1 Use of indicators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

3.4.2 Use of meta-analysis.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

 3.5 Data availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

3.5.1 Transferring ecological information from one site to another. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

 3.6 Directions for ecological research to support valuation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

 3.7 Conclusions and recommendations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

4 Methods for assessing value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

 4.1 Criteria for choosing valuation methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

4.1.1 Suggested criteria. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

 4.2 An expanded set of methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

4.2.1 Measures of attitudes, preferences, and intentions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

4.2.2 Economic methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
x

4.2.3 Civic valuation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

4.2.4 Decision science methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

4.2.5 Ecosystem benefit indicators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

4.2.6 Biophysical ranking methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

4.2.7 Methods using cost as a proxy for value. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

 4.3 Transferring value information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

4.3.1 Transfer of information about economic benefits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

4.3.2 Transfer methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

4.3.3 Challenges regarding benefits transfer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

4.3.4 Improving transfers of value information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

 4.4 Conclusions and recommendations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

5 Cross-cutting issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

 5.1 Deliberative processes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

 5.2. Analysis and representation of uncertainties in ecological valuation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

5.2.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

5.2.2 Sources of uncertainty in ecological valuations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

5.2.3 Approaches to assessing uncertainty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

5.2.4 Communicating uncertainties in ecological valuations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

5.2.5 Using uncertainty assessment to guide research initiatives. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

 5.3 Communication of ecological valuation information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

5.3.1 Applying general communication principles to ecological valuation. . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

5.3.2 Special communication challenges related to ecological valuation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

 5.4 Conclusions and recommendations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

6 Applying the approach in three EPA decision contexts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

 6.1 Valuation for national rule making. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

6.1.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

6.1.2 Valuation in the national rule making context. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

6.1.3 Implementing the proposed approach. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

6.1.4 Summary of recommendations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

 6.2 Valuation in regional partnerships. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

6.2.1 EPA’s role in regional-scale value assessment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

6.2.2 Case study: Chicago Wilderness. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

6.2.3 Other case studies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

6.2.4 Summary and recommendations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

 6.3 Valuation for site-specific decisions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

6.3.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

6.3.2 Opportunities for using valuation to inform remediation and redevelopment decisions.. . . . . . . . . . . . . 88

6.3.3 Illustrative site-specific examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

6.3.4 Summary of recommendations for valuation for site-specific decisions. . . . . . . . . . . . . . . . . . . . . . . . . . 99

7 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
xi

 7.1 An expanded, integrated valuation approach. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

 7.2 Early identification of how actions may contribute to human welfare. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

 7.3 Prediction of ecological responses in value-relevant terms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

 7.4 Valuation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

 7.5 Other cross-cutting issues. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

7.5.1 Deliberative processes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

7.5.2 Uncertainty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

7.5.3 Communication of valuation information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

 7.6 Context-specific recommendations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

7.6.1 National rule making. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

7.6.2 Regional partnerships. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

7.6.3 Site-specific decisions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

 7.7 Recommendations for research and data sharing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

Appendix A: Web-accessible materials on ecological valuation developed by or for the C-VPESS . . . . . . . . 106

Appendix B: Table of acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

Endnotes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
xii

Lists of Figures, Tables, and Text Boxes 

Figures

Figure 1: Process for implementing an expanded and integrated approach to ecological valuation. . . . . . . . . . . . . . 24

Figure 2: Illustration from Covich et al., (2004) showing relationships of major functional types 

to ecological services. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Figure 3: Graphical depiction of ecological production functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Figure 4: Ecological impacts of CAFOs at multiple scales. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Figure 5: Integration of valuation information with the traditional remediation and redevelopment process. . . . . . . 89

Figure 6: Framework for net environmental benefit analysis (from Efroymson et al., 2003). . . . . . . . . . . . . . . . . . . 97

Tables 

Table 1: A classification of concepts of value as applied to ecological systems and their services. . . . . . . . . . . . . . . 14

Table 2: Key features of an expanded and integrated approach to valuation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Table 3: Methods considered by the committee for possible use in valuation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Table 4: Table of alternative unit value transfers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Text boxes 

Text box 1 – Valuation and the aquaculture effluent guidelines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Text box 2 – Valuation and the CAFO effluent guidelines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Text box 3 – Ecological benefit assessment as part of the prospective study 

of the economic benefits of the Clean Air Act Amendments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Text box 4 – Charles-George Landfill: An urban example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Text box 5 – DuPage Country Landfill: An urban example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Text box 6 – Avtex Fibers site: A suburban example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Text box 7 – Leviathan Mine Superfund site: An ex-urban example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Text box 8 – Net environmental benefit analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
1

SABValuing the Protection of 

Ecological Systems and Services 

A Report of the EPA Science Advisory Board 
2

EPA’s Science Advisory Board (SAB) created the 

Committee on Valuing the Protection of Ecological 

Systems and Services (C-VPESS) to offer advice to the 

Agency on how EPA might better assess the value of 

protecting ecological systems and services. As used in 

this report, the term “valuation” refers to the process 

of measuring values associated with a change in an 

ecosystem, its components, or the services it provides. 

The SAB charged the committee to: 

o Assess EPA’s needs for valuation to support decision 

making.

o Assess the state of the art and science of valuing the 

protection of ecological systems and services.

o Identify key areas for improving knowledge, 

methodologies, practice, and research at the Agency.

This report provides recommendations to the Agency 

for improving EPA’s current approach to ecological 

valuation and for supporting new research to strengthen 

the science base for future valuations.

General findings and advice

EPA’s mission to protect human health and the 

environment requires the Agency to understand and 

protect ecosystems and the numerous and varied services 

they provide. Ecosystems play a vital role in our lives, 

providing such services as water purification, flood 

protection, pollination, recreation, aesthetic satisfaction, 

and the control of diseases, pests, and climate. EPA’s 

regulations, programs, and other actions, as well as the 

decisions of other agencies with which EPA partners, can 

affect ecosystem conditions and the flow of ecosystem 

services at a local, regional, national, or global scale. To 

date, however, policy analyses have typically focused on 

only a limited set of ecological factors.

Just as policy makers at EPA and elsewhere need 

information about how their actions might affect human 

health in order to make good decisions, they also need 

information about how ecosystems contribute to society’s 

well-being and how contemplated actions might affect 

those contributions. Such information can also help 

inform the public about the need for ecosystem protection, 

the extent to which specific policy alternatives address 

that need, and the value of the protection.

Valuation of ecological systems and services is 

important in national rule makings, where executive 

orders often require cost-benefit analyses and several 

statutes require weighing of benefits and costs. Regional 

EPA offices can find valuation important in setting 

program priorities and in assisting other governmental 

and non-governmental organizations in choosing among 

environmental options and communicating the importance 

of their actions to the public. Ecological valuation can also 

help EPA to improve the remediation of hazardous waste 

sites and make other site-specific decisions.

This report describes and illustrates how EPA can use 

an “expanded and integrated approach” to ecological 

valuation. The proposed approach is “expanded” in 

seeking to assess and quantify a broader range of 

values than EPA has historically addressed and through 

consideration of a larger suite of valuation methods. The 

proposed approach is “integrated” in encouraging greater 

collaboration among a wide range of disciplines, including 

ecologists, economists, and other social and behavioral 

scientists, at each step of the valuation process.

Value is not a single, simple concept. People may 

use many different concepts of value when assessing 

the protection of ecosystems and their services. For this 

reason, the committee considered several value concepts. 

These included measures of value based on people’s 

preferences for alternative goods and services (measures 

of attitudes or judgments, economic values, communitybased values, and constructed preferences) and measures 

based on biophysical standards of potential public 

importance (such as biodiversity or energy flows). 

To date, EPA has primarily sought to measure 

economic benefits, as required in many settings by 

statute or executive order. The report concludes that 

information based on some other concepts of value 

may also be a useful input into decisions affecting 

ecosystems, although members of the committee hold 

different views regarding the extent to which specific 

methods and concepts of values should be used in 

particular policy contexts.

In addition, the Agency’s value assessments 

have often focused on those ecosystem services or 

components for which EPA has concluded that it could 

relatively easily measure economic benefits, rather than 

on those services or components that may ultimately be 

most important to society. Such a focus can diminish the 

relevance and impact of a value assessment. This report 

therefore advises the Agency to identify the services and 

components of likely importance to the public at an early 

stage of a valuation and then to focus on characterizing, 

measuring, and assessing the value of the responses of 

those services and components to EPA’s actions. 

EPA should seek to measure the values that people 

hold and would express if they were well informed about 

the relevant ecological and human well-being factors 

Executive Summary
3

involved. This report therefore advises EPA to explicitly 

incorporate that information into the valuation process 

when changes to ecosystems and ecosystem services are 

involved. Valuation surveys, for example, should provide 

relevant ecological information to survey respondents. 

Valuation questions should be framed in terms of 

services or changes that people understand and can value. 

Likewise, deliberative processes should convey relevant 

information to participants. The report also encourages 

EPA to consider public education efforts where gaps exist 

between public knowledge and scientific understanding of 

the contributions of ecological processes.

All steps in the valuation process, beginning with 

problem formulation and continuing through the 

characterization, representation, and measurement 

of values, require information and input from a wide 

variety of disciplines. Instead of ecologists, economists, 

and other social and behavioral scientists working 

independently, experts should collaborate throughout the 

process. Ecological models need to provide usable inputs 

for valuation, and valuation methods need to incorporate 

important ecological and biophysical effects. 

Of course, EPA conducts ecological valuations within 

a set of institutional, legal, and practical constraints. These 

constraints include substantive directives, procedural 

requirements relating to timing and oversight, and resource 

limitations (both monetary and personnel). For example, 

the preparation of regulatory impact analyses (RIAs) for 

proposed regulations is subject to Office of Management 

and Budget (OMB) oversight and approval. OMB’s Circular 

A-4 on Regulatory Analysis makes it clear that RIAs should 

include an economic analysis of the benefits and costs of 

proposed regulations conducted in accordance with the 

methods and procedures of standard welfare economics. At 

the same time, the circular provides that where EPA cannot 

quantify a benefit in monetary terms, EPA should still try 

to measure the effect of the Agency’s action in terms of its 

physical units or, where such quantification is not possible, 

describe the effect and its value in qualitative terms. 

Regional and site-specific programs and decisions, which 

are not subject to the same legal requirements as national 

rule makings, can offer useful opportunities for testing and 

implementing a broader suite of valuation methods.

Three key recommendations

The committee’s principal advice to EPA, as noted 

above, is to pursue an expanded, integrated approach 

to assessing the value of the ecological effects of its 

regulations, programs, and other actions. The report 

contains three overarching recommendations for 

achieving this goal. In particular, the report recommends 

that the Agency: 

1. Identify early in the valuation process the ecological 

responses that are likely to be of greatest importance 

to people, using information about ecological 

importance, likely human and social consequences, and 

public concerns. EPA should then focus its valuation 

efforts on those responses. This will help expand the 

range of ecological responses that EPA characterizes or 

quantifies or for which it estimates values.

2. Predict ecological responses in terms that are relevant 

to valuation. Prediction of ecological responses is a 

key step in valuation efforts. To predict responses in 

value-relevant terms, EPA should focus on the effects 

of decisions on ecosystem services or other ecological 

features that are of direct concern to people. This, in 

turn, will require the Agency to go beyond merely 

predicting the biophysical effects of decisions and to 

map those effects to responses in ecosystem services 

or components that the public values. 

3. Consider the use of a wider range of possible 

valuation methods, either to provide information 

about multiple sources and concepts of value or to 

better capture the full range of contributions stemming 

from ecosystem protection. In considering the use 

of different methods, however, care must be taken 

to ensure that only methods that meet appropriate 

validity and related criteria are used, and to recognize 

that different methods may measure different things 

and thus not be directly additive or comparable. This 

report therefore calls on EPA to develop criteria to 

evaluate and determine the appropriate use of each 

method. EPA should also carefully evaluate its use of 

value information collected at one site in the valuation 

of policy impacts at a different site (transfers of 

value information) and more fully characterize and 

communicate uncertainty for all valuations.

Implementing the recommendations

The report provides specific advice on how to 

achieve these overarching recommendations. The report 

proposes a large number of steps, some of which can be 

implemented in the short run, but others of which will 

require investments in research or method development, 

policy changes, and/or new resources. EPA should begin 

the process of adopting a more expanded, integrated 

approach to ecological valuation by prioritizing 

the steps that it will take to accomplish the report’s 

recommendations, taking into account the relative ease 

and cost of each potential step.

Implementing recommendation #1

The first major recommendation, as noted, is to 

identify from an early stage in the valuation process the 

ecological responses that contribute to human well-being 

and are likely to be of greatest importance to people, and 

then to focus valuation efforts on these responses. To 

accomplish this, the report recommends that EPA:

o Begin each valuation by developing a conceptual 

model of the relevant ecosystem and the ecosystem 

services that it generates. This model should serve as 

a road map to guide the valuation.
4

o Involve staff throughout EPA, as well as outside experts 

in the biophysical and social sciences, in constructing 

the conceptual model. 

o EPA should also seek information about relevant public 

concerns and needs. EPA can identify public concerns 

through a variety of methods, drawing on either 

existing knowledge or interactive processes designed 

to elicit public input.

o Incorporate new information into the model, in an 

iterative process, as the value assessment proceeds.

Implementing recommendation #2

Ecological valuation requires both prediction of 

ecological responses and an estimation of the value 

of those responses. To predict ecological responses in 

value-relevant terms, EPA should focus on the effects 

of decisions on ecosystem services and should map 

responses in ecological systems to responses in services 

or ecosystem components that the public can directly 

value. Unfortunately, the science needed to do this has 

been limited, presenting a barrier to effective valuation 

of ecological systems and services. To better predict 

ecological responses in value-relevant terms in the 

future, EPA should:

o Identify and develop measures of ecosystem services 

that are relevant to and directly useful for valuation. 

This will require increased interaction within EPA 

between natural and social scientists. In identifying 

and assessing the value of services, EPA should 

describe them in terms that are meaningful and 

understandable to the public.

o Where possible, use ecological production functions 

to estimate how effects on the structure and function 

of ecosystems, resulting from the actions of EPA 

or partnering agencies, will affect the provision of 

ecosystem services for which values can then be 

estimated. Development of a broad suite of ecological 

production functions currently faces numerous 

challenges and can benefit from new research.

o Where complete ecological production functions do 

not exist:

• Examine available ecological indicators that are 

correlated with changes in ecosystem services 

to provide information about the effects of 

governmental actions on those services.

• Use methods such as meta-analysis that can 

provide general information about key ecological 

relationships important in the valuation.

o Support all ecological valuations by ecological 

models and data sufficient to understand and 

estimate the likely ecological responses to the major 

alternatives being considered by decision makers. 

Analyze and report on the uncertainty involved in 

biophysical projections.

Implementing recommendation #3

In characterizing, measuring, or quantifying the 

value of ecological responses to actions by EPA or other 

agencies, EPA should consider the use of a broader 

suite of valuation methods than it has historically 

employed. As summarized in Table 3 at pages 42-

43, this report considers the possible use of not only 

economic methods, but also such alternative methods 

as measures of attitudes, preferences, and intentions; 

civic valuation; decision science approaches; ecosystem 

benefit indicators, biophysical ranking methods; and 

cost as a proxy for value. A broader suite of methods 

could allow EPA to better capture the full range of 

contributions stemming from ecosystem protection and 

the multiple sources of value derived from ecosystems. 

Non-economic valuation methods may also usefully 

support and improve economic valuation by helping to 

identify the ecological responses that people care about, 

by providing indicators of economic benefits that EPA 

cannot monetize using economic valuation, and by 

offering supplemental information outside strict benefitcost analysis. In this regard, EPA should:

o Pilot and evaluate the use of alternative methods 

where legally permissible and scientifically 

appropriate. 

o Develop criteria to determine the suitability of 

alternative methods for use in specific decision 

contexts. An over-arching criterion should be 

validity – i.e., how well the method measures the 

underlying construct that it is intended to measure. 

Given differences in premises, goals, concerns, and 

external constraints, appropriate uses will vary among 

methods and contexts. Different methods are also at 

different stages of development and validation.

EPA could also improve its ecological valuations by 

carefully evaluating the transfer of value information 

and more fully characterizing and communicating 

uncertainty. In this regard, EPA should:

o Identify relevant criteria for determining the 

appropriateness of the transfer of value information. 

These criteria should consider similarities and 

differences in societal preferences and the nature of 

the biophysical systems between the study site and 

the policy site. Using these criteria, EPA analysts and 

those providing oversight should flag problematic 

transfers and clarify assumptions and limitations of 

the study-site results.

o Go beyond simple sensitivity analysis in assessing 

uncertainty, and make greater use of approaches, such 

as Monte Carlo analysis, that provide more useful 

and appropriate characterizations of uncertainty in 

complex contexts such as ecological valuation. 

o Provide information to decision makers and the public 

about the level of uncertainty involved in ecological 

valuation efforts. EPA should not relegate uncertainty 
5

analyses to appendices but should ensure that a 

summary of uncertainty is given as much prominence 

as the valuation estimate itself, with careful attention 

to how recipients are likely to understand the 

uncertainties. EPA should also explain qualitatively any 

limitations in the uncertainty analysis.

While EPA should improve its characterization 

and reporting of uncertainty, the mere existence of 

uncertainty should not be an excuse for delaying actions 

where the benefits of immediate action outweigh the 

value of attempting to further reduce the uncertainty 

Some uncertainty will always exist.

Context-specific recommendations

The report also examines how to implement an 

expanded and integrated approach to ecological valuation 

in three specific contexts: national rule makings, regional 

partnerships, and local site-specific decisions.

National rule making

Applying the expanded and integrated valuation 

approach to national rule making will entail some 

challenges, but also offers important opportunities for 

improvement. EPA can implement some, but not all, of 

the committee’s recommendations using the existing 

knowledge base. The committee also recognizes that 

EPA must conduct valuations for national rule making 

in compliance with statutory and executive mandates. 

Specific recommendations for improving valuations for 

national rule making in the short run include:

o EPA should develop a conceptual model at the 

beginning of each valuation, as discussed above, 

to serve as a guide or road map. To ensure that the 

model captures the ecological properties and services 

that are potentially important to people, EPA should 

incorporate input both from relevant science and 

about public preferences and concerns. 

o The Agency should address site-specific variability 

in the impact of a rule by producing case studies 

for important ecosystem types and then aggregating 

across the studies where information about the 

distribution of ecosystem types and affected 

populations is available.

o EPA should not compromise the quality of its 

valuations by inappropriately transferring information 

about values. Where the values of ecosystem 

services are primarily local, the Agency can rely 

on scientifically-sound value transfers using prior 

valuations at the local level. However, for services 

valued more broadly, EPA should draw from studies 

with broad geographical coverage (in terms of both 

the changes that are valued and the population whose 

values are assessed).

o EPA should pilot and evaluate the use of a broader 

suite of valuation methods to support and improve 

RIAs. Although OMB Circular A-4 requires RIAs 

to monetize benefits to the extent possible using 

economic valuation methods, other methods could be 

useful in the following ways: 

• Helping to identify early in the process the 

ecosystem services that are likely to be of concern 

to the public and that should therefore be the focus 

of the benefit-cost analysis.

• Addressing the requirement in Circular A-4 to 

provide quantitative or qualitative information 

about the possible magnitude of benefits (and 

costs) when they cannot be monetized using 

economic valuation.

• Providing supplemental information outside the 

formal benefit-cost analysis about sources and 

concepts of value that might be of interest to 

EPA and the public but not reflected in economic 

values.

o To ensure that RIAs do not inappropriately focus only 

on impacts that have been monetized, EPA should 

also report on other ecological impacts in appropriate 

units where possible, as required by Circular A-4. The 

Agency should label aggregate monetized economic 

benefits as “total economic benefits that could be 

monetized,” not as “total benefits.”

o EPA should include a separate chapter on uncertainty 

characterization in each RIA or value assessment.

Regional partnerships

The committee sees great potential in undertaking a 

comprehensive and systematic approach to estimating 

the value of protecting ecosystems and services at a 

regional scale, in part because of the effectiveness 

with which EPA regional offices can partner with other 

agencies and state and local governments. Regionalscale analyses hold great potential to inform decision 

makers and the public about the value of protecting 

ecosystems and services, but this potential is at present 

largely unrealized. The general recommendations of 

this report provide a guide for regional valuations. 

Regional valuations are a particularly appropriate 

setting in which to test alternative valuation methods 

because there are generally fewer legal directives 

or restrictions regarding the value concepts and 

methods to be used. The report also includes several 

recommendations specific to regions, including:

o EPA should encourage its regions to engage in 

valuation efforts to support decision making both by 

the regions and by partnering governmental agencies.

o EPA should provide adequate resources to EPA 

regional staff to develop the expertise needed to 

undertake comprehensive and systematic studies of 

the value of protecting ecosystems and services.

o To ensure that regions can learn from valuation 

efforts by other regions, EPA regional offices should 
6

document valuation efforts and share them with 

other regional offices, EPA’s National Center for 

Environmental Economics, and EPA’s Office of 

Research and Development. 

Site-specific decisions

Incorporation of ecological valuation into local 

decisions about the remediation and redevelopment 

of contaminated sites can help enhance the ecosystem 

services provided by such sites in the long run and thus 

the sites’ contributions to local well-being. The general 

recommendations of the report provide a useful guide 

for such site-specific valuations. The report also includes 

several recommendations of particular relevance to sitespecific decisions, including:

o EPA should provide regional offices with the staff and 

resources needed to effectively incorporate ecological 

valuation into the remediation and redevelopment of 

contaminated sites.

o EPA should determine the ecosystem services and 

values important to the community and affected 

parties at the beginning of the remediation and 

redevelopment process.

o EPA should adapt current ecological risk assessment 

practices to incorporate ecological production 

functions and predict the effects of remediation and 

redevelopment options on ecosystem services.

o EPA should communicate information about 

ecosystem services in discussing options for 

remediation and redevelopment with the public and 

affected parties.

o EPA should create formal systems and processes 

to foster information-sharing about ecological 

valuations at different sites.

Recommendations for research and 

data sharing

The report provides several recommendations for 

EPA’s research programs that are designed to provide 

the ecological information needed for valuation, 

develop and test valuation methods, and share data. 

In a number of cases, these recommendations parallel 

research plans that have been developed by the Office 

of Research and Development and other Agency 

groups. As an over-arching recommendation, the report 

advises EPA to more closely coordinate its research 

programs on the valuation of ecosystem services and 

to develop links with other governmental agencies 

and organizations engaged in valuation and valuation 

research. It advises, at a more general level, fostering 

greater interaction between natural scientists and social 

scientists in identifying relevant ecosystem services and 

developing and implementing processes for measuring 

them and estimating their value. The report identifies 

important research areas but does not attempt to rank or 

prioritize among all of its research recommendations. 

The committee recommends that EPA develop a 

research strategy, building on the recommendations 

in this report, that identifies “low-hanging fruit” and 

prioritizes studies likely to have the largest payoff for 

their cost in both advancing valuation methods and 

providing valuation information of importance to EPA 

in its work.

To develop EPA’s ability to determine and quantify 

ecological responses to governmental decisions, the 

Agency should:

o Support the development of quantitative ecosystem 

models and baseline data on ecological stressors and 

ecosystem service flows that can support valuation 

efforts at the local, regional, national, and global levels.

o Promote efforts to collect data that can be used to 

parameterize ecological models for site-specific 

analysis and case studies or that can be transferred or 

scaled to other contexts.

o Carefully plan and actively pursue research to 

develop and generate ecological production functions 

for valuation, including Office of Research and 

Development and STAR research on ecological 

services and support for modeling and methods 

development. The committee believes that this is a 

research area of high priority.

o Given the complexity of developing and using 

complete ecological production functions, continue 

and accelerate research to develop key indicators 

for use in ecological valuation. Such indicators 

should meet ecological and social science criteria for 

effectively simplifying and synthesizing underlying 

complexity and link to an effective monitoring and 

reporting program. 

To develop EPA’s capabilities for estimating the value 

of ecological responses to governmental decisions, EPA 

should:

o Support new studies and the development of new 

methodologies that will enhance the future transfer 

of value information and other means of generalizing 

ecological value assessments, particularly at the 

national level. Such research should include national 

surveys related to ecosystem services with broad (rather 

than localized) implications so that value estimates 

might be usable in multiple rule-making contexts. This 

should also be a priority area for research.

o Invest in research designed to reduce uncertainties 

associated with ecological valuation through data 

collection, improvements in measurement, theory 

building, and theory validation. 

o Incorporate the research needs of regional offices for 

systematic valuation studies in future calls by EPA for 

extramural ecological valuation research proposals.

To access and share information to enhance the 

Agency’s capabilities for ecological valuation, EPA 

should:
7

o Work with other federal agencies and scientific 

organizations such as the National Science 

Foundation to encourage the sharing of ecological 

data and the development of more consistent 

ecological measures that are useful for valuation 

purposes. A number of governmental organizations, 

such as the United States Department of Agriculture 

and the Fish & Wildlife Service, are working on 

biophysical modeling and valuation, and EPA could 

usefully partner with them.

o Support efforts to develop Web-based databases 

of existing valuation studies that could be used 

in transferring value information. The databases 

should include valuation studies across a range of 

ecosystems and ecosystem services. The databases 

should also carefully describe the characteristics and 

assumptions of each study, in order to increase the 

likelihood that those studies most comparable to new 

valuations can be identified for use. 

o Support the development of national-level databases 

of information useful in the development of new 

valuation studies. Such information should include 

data on the joint distribution of ecosystem and 

human population characteristics that are important 

determinants of the value of ecosystem services.

o Develop processes and information resources so 

that EPA staff in one region or office of the Agency 

can learn effectively from valuation efforts being 

undertaken elsewhere within the Agency.
8

1

Introduction

The mission of the Environmental Protection Agency 

(EPA) is to protect human health and the environment. 

During its history, EPA has focused much of its decisionmaking expertise on the first part of this mission, in 

particular the risks to human health from chemical 

stressors in the environment. Although protecting human 

health is the bedrock of EPA’s traditional expertise, the 

broad mission of EPA goes beyond this. EPA’s Strategic 

Plan (U.S. Environmental Protection Agency [EPA], 

2006a) explicitly identifies the need to ensure “healthy 

communities and ecosystems” as one of its five major 

goals. Agency publications and independent sources 

document EPA’s efforts to protect ecological resources 

– and its authority for doing so (EPA, 1994; EPA Risk 

Assessment Forum, 2003; EPA Science Advisory Board, 

2000; Hays, 1989; Russell, 1993). 

EPA’s mission to protect the environment requires that 

the Agency understand and protect ecological systems. 

Ecologists use the term “ecosystem” to describe the 

dynamic complex of plant, animal, and microorganism 

communities and non-living environment interacting 

as a system. For example, a forest ecosystem consists 

of the trees in the forest, all other living organisms, and 

the non-living environment with which they interact. 

Ecosystems provide basic life support for human and 

animal populations and are the source of spiritual, 

aesthetic, and other human experiences that are valued in 

many ways by many people. 

There has been a growing recognition of the 

numerous and varied services that ecosystems provide to 

human populations through a wide range of ecological 

functions and processes (e.g., Daily, 1997). Ecosystems 

not only provide goods and services that are directly 

consumed by society such as food, timber, and water; 

they also provide services such as flood protection, 

disease regulation, pollination, and the control of 

diseases, pests, and climate. There is, too, increasing 

recognition of the impact of human activities on 

ecosystems (e.g., Millennium Ecosystem Assessment 

Board, 2003; Millennium Ecosystem Assessment, 2005). 

Among the examples of this impact are traditional air 

and water pollution (such as sulfur dioxide emissions, 

ground-level ozone, and eutrophication), as well as 

global warming; changes in the nitrogen cycle; invasive 

species; aquifer depletion, and land conversions that lead 

to deforestation or loss of wetlands and biodiversity. 

Given the vital role that ecosystems play in our 

lives, the state of these systems and the flow of services 

they provide have important human implications. EPA 

actions, including regulations, rules, programs, and 

policy decisions, can affect the condition of ecosystems 

and the flow of ecosystem services. These effects can 

occur narrowly, at a local or a regional scale, or broadly, 

at a national or global scale. 

Despite the importance of these ecological effects, 

EPA policy analyses have tended to focus on a limited 

set of ecological endpoints, such as those specified in 

tests for pesticide regulation (e.g., effects on the survival, 

growth, and reproduction of aquatic invertebrates, fish, 

birds, mammals, and terrestrial and aquatic plants) or 

specified in laws administered by the Agency (e.g., 

mortality to fish, birds, plants, and animals) (EPA Risk 

Assessment Forum, 2003).1

 Given EPA’s responsibility 

to ensure healthy communities and ecosystems, the 

Agency should consider the full range of effects that 

its actions will have. Thus, in addition to evaluating 

impacts on human health and other environmental goals, 

EPA should evaluate the effects of its actions, wherever 

relevant, on individual organisms and plant and animal 

populations, and on the structure and functions of 

communities and ecosystems. Such evaluations should 

be comprehensive and integrated.

To promote good decision making, policy 

makers also require information about how much 

ecosystems contribute to society’s well-being. EPA 

increasingly recognizes this need. The stated goal 

of EPA’s Ecological Benefits Assessment Strategic 

Plan is to “help improve Agency decision making 

by enhancing EPA’s ability to identify, quantify, and 

value the ecological benefits of existing and proposed 

policies” (2006c, p. xv). Information about the value of 

ecosystems and the associated effects of EPA actions 

can also help inform the public about the need for 

ecosystem protection, the extent to which specific 

policy alternatives address that need, and the value of 

the protection compared to the costs. 

Despite EPA’s stated mission and mandates, a gap exists 

between the need to understand and protect ecological 

systems and services and EPA’s ability to address this need. 

This report is a step toward filling that gap. It describes 

how an integrated and expanded approach to ecological 

valuation can help the Agency describe and measure the 

value of protecting ecological systems and services, thus 

better meeting its overall mission. The terms ecological 

valuation or valuing ecological change, as used in this 

report, refer to the process of estimating or assessing the 

value of a change in an ecosystem, its components, or the 

services it provides. The values at interest here are those of 

the public, and this report discusses how to appropriately 

estimate or assess them.
9

This report was prepared by the Committee on 

Valuing the Protection of Ecological Systems and 

Services (C-VPESS) of EPA’s Science Advisory 

Board (SAB). The SAB saw a need to complement the 

Agency’s ongoing work by offering advice on how 

EPA might better value the protection of ecological 

systems and services and how that information could 

support decision making to protect ecological resources. 

Therefore, in 2003, the SAB Staff Office formed 

C-VPESS,2

 a group of experts in decision science, 

ecology, economics, engineering, law, philosophy, 

political science, and psychology, with a particular 

understanding of ecosystem protection. The committee’s 

charge was to undertake a project to improve the 

Agency’s ability to value ecological systems and 

services.3

 The SAB set the following goals: 

o Assessing Agency needs for valuation to support 

decision making

o Assessing the state of the art and science of valuing 

protection of ecological systems and services 

o Identifying key areas for improving knowledge, 

methodologies, practice, and research at EPA

This report provides advice for strengthening the 

Agency’s approaches for valuing the protection of 

ecological systems and services, facilitating the use of 

these approaches by decision makers, and investing 

in the research areas needed to bolster the science 

underlying ecological valuation.4

 It identifies the need 

for an expanded and integrated approach for valuing 

EPA’s efforts to protect ecological systems and services. 

The report also recognizes and highlights issues that 

need to be addressed in using and improving current 

valuation methods and recommends new research 

to address these needs. It provides advice to the 

Administrator, EPA managers, EPA scientists and 

analysts, and other staff across the Agency concerned 

with ecological protection. It addresses valuation in a 

broad set of contexts, including national rule making, 

regional decision making, and site-specific decisions that 

protect ecological systems and services. 

This report appears at a time of lively interest 

internationally, nationally, and within EPA in valuing 

the protection of ecological systems and services. Since 

the establishment of the SAB C-VPESS, a number of 

major reports have focused on ways to improve the 

characterization of the important role of ecological 

resources (Silva and Pagiola, 2003; National Research 

Council [NRC], 2004; Pagiola, von Ritter et al., 2004; 

Millennium Ecosystem Assessment, 2005).5

 In addition, 

the Agency itself has engaged in efforts to improve 

ecological valuation. The most recent product of these 

efforts is the Ecological Benefits Assessment Strategic 

Plan noted above (EPA, 2006c). EPA also has sought to 

strengthen the science supporting ecological valuation 

through the extramural Science to Achieve Results 

(STAR) grants program and the Office of Research and 

Development’s ecosystem-services research program 

(EPA Science Advisory Board, 2008b). 

The committee has both learned from and built 

upon these recent efforts. However, C-VPESS 

distinguishes its work from many of the earlier efforts 

in several key ways. First, C-VPESS considers EPA its 

principal audience. In particular, C-VPESS analyzes 

ways in which EPA can value its own contributions 

to the protection of ecological systems and services, 

so that the Agency can make better decisions in its 

eco-protection programs. Many of the recent studies, 

including the Millennium Assessment and National 

Research Council report, do not consider the specific 

policy contexts or constraints faced by EPA. Second, 

most, but not all, of the previous work has concentrated 

on economic valuation, and monetary valuation in 

particular. C-VPESS, by contrast, is interdisciplinary 

and does not focus solely on monetary or economic 

methods or values. 

The report is structured as follows. Chapter 2 

provides an overview of the conceptual framework 

and general approach advocated by the committee. It 

discusses fundamental concepts as well as the current 

state of ecological valuation at EPA. Most importantly, 

it identifies the need for an expanded and integrated 

approach to ecological valuation at EPA and describes 

the key features of this approach. Subsequent chapters 

develop in more detail the basic principles outlined 

in chapter 2, focusing on implementation. Chapter 3 

discusses predicting the effects of EPA actions and 

decisions on ecological systems and services. Chapter 
10

4 examines a variety of methods for valuing these 

changes. More detailed descriptions of the valuation 

methods, developed by members of the C-VPESS, 

along with a separate discussion of survey issues 

relevant to ecological valuation, are available on 

the SAB Web site at http://yosemite.epa.gov/sab/

sabproduct.nsf/WebBOARD/C-VPESS_Web_Methods_

Draft?OpenDocument. Chapter 5 covers cross-cutting 

issues related to deliberative approaches, uncertainty, 

and communication. Recognizing that implementation 

of the process can vary depending on the decision 

context, chapter 6 discusses implementation in three 

specific contexts where ecological valuation could 

play an important role in EPA analysis: national rule 

making, regional partnerships, and site-specific decisions 

(looking specifically at cleanup and restoration). Finally, 

chapter 7 provides a summary of the report’s major 

findings and recommendations.

Everyone at EPA involved in the design or 

implementation of valuation efforts, or in the 

establishment of policy for valuations, will find the first 

five chapters of this report relevant and important to 

their work. Section 6.1 of this report, which addresses 

national rule making, will be of particular interest to 

EPA officials in Washington, DC. Sections 6.2 and 6.3, 

which address regional partnerships and site-specific 

decisions, will be of special interest to regional offices, 

as well as those national officials responsible for 

overseeing regional policy. EPA staff who are looking 

for a detailed discussion of specific methods will find the 

information on the SAB Web site useful. B
11
12

2

Conceptual framework

2.1 An overview of key concepts

2.1.1 The concept of ecosystems

As noted in chapter 1, the term “ecosystem” describes 

a dynamic complex of plant, animal, and microorganism 

communities and their non-living environment, 

interacting as a system. Ecosystems encompass all 

organisms within a prescribed area, including humans. 

Ecosystem functions or processes are the characteristic 

physical, chemical, and biological activities that 

influence the flows, storage, and transformation of 

materials and energy within and through ecosystems. 

These activities include processes that link organisms 

with their physical environment (e.g., primary 

productivity and the cycling of nutrients and water) and 

processes that link organisms with each other, indirectly 

influencing flows of energy, water, and nutrients (e.g., 

pollination, predation, and parasitism). These processes 

in total describe the functioning of ecosystems.

2.1.2 The concept of ecosystem services

Ecosystem services are the direct or indirect 

contributions that ecosystems make to the well-being of 

human populations. Ecosystem processes and functions 

contribute to the provision of ecosystem services, but 

they are not synonymous with ecosystem services. 

Ecosystem processes and functions describe biophysical 

relationships that exist whether or not humans benefit 

from them. These relationships generate ecosystem 

services only if they contribute to human well-being, 

defined broadly to include both physical well-being and 

psychological gratification. Thus, ecosystem services 

cannot be defined independently of human values. 

The Millennium Ecosystem Assessment uses the 

following categorization of ecosystem services: 

o Provisioning services – services from products 

obtained from ecosystems. These products include 

food, fuel, fiber, biochemicals, genetic resources, and 

fresh water. Many, but not all, of these products are 

traded in markets. 

o Regulating services – services received from the 

regulation of ecosystem processes. This category 

includes services that improve human well-being 

by regulating the environment in which people live. 

These services include flood protection, human 

disease regulation, water purification, air quality 

maintenance, pollination, pest control, and climate 

control. These services are generally not marketed but 

many have clear value to society.

o Cultural services – services that contribute to 

the cultural, spiritual, and aesthetic dimensions 

of people’s well-being. They also contribute to 

establishing a sense of place. 

o Supporting services – services that maintain basic 

ecosystem processes and functions such as soil 

formation, primary productivity, biogeochemistry, 

and provisioning of habitat. These services affect 

human well-being indirectly by maintaining 

processes necessary for provisioning, regulating, and 

cultural services.

As this categorization suggests, the Millennium 

Ecosystem Assessment adopts a very broad definition of 

ecosystem services, limited only by the requirement of 

a direct or indirect contribution to human well-being.6

This broad approach recognizes the myriad ways in 

which ecosystems support human life and contribute to 

human well-being. Boyd and Banzhaf (2006) propose a 

narrower definition that focuses only on those services 

that are end products of nature, i.e., “components of 

nature, directly enjoyed, consumed or used to yield 

human well-being” (emphasis added). They stress the 

need to distinguish between intermediate products and 

final (or end) products and include only final outputs in 

the definition of ecosystem services, because these affect 

people most directly and consequently are what people 

are most likely to understand. In addition, the focus on 

final products reduces the potential for double-counting, 

which can arise if both intermediate and final products 

or services are valued. Under this definition, ecosystem 

functions and processes, such as nutrient recycling, are 

not considered services. Although they contribute to 

the production of ecological end products or outputs, 

they are not outputs themselves. Likewise, because 

supporting services contribute to human well-being 

indirectly rather than directly, they are recognized as 

being potentially very important but are not included in 

Boyd and Banzhaf’s definition of ecosystem services.

Regardless of the specific definition used, ecosystem 

services play a key role in the evaluation of policies that 

affect ecosystems because they reflect contributions 

of the ecosystem to human well-being. Simply listing 

the services derived from an ecosystem, using the best 

available ecological, social, and behavioral sciences, 

can help ensure appropriate recognition of the full range 

of potential ecological responses to a given policy and 

their effects on human well-being. It can also help make 

the analysis of the role of ecosystems more transparent 

and accessible. To ensure consideration of the full range 

of contributions, this report uses the term ecosystem 

services to refer broadly to both intermediate and final/

end services. In specific valuation contexts, however, it 
13

may be important to identify whether the service being 

valued is an intermediate or a final service (see sections 

2.1.4, 2.3.3, and 3.3.2 for related discussions). 

The committee recognizes that ecosystems can be 

important not only because of the services they provide 

to humans directly or indirectly, but also for other 

reasons, including respect for nature based on moral 

or spiritual beliefs and commitments. The committee’s 

name includes reference to the protection of both 

ecosystem services and the ecosystems themselves. 

Thus, although much of this report focuses on ecosystem 

services, the discussion of ecological protection and 

valuation applies both to ecosystem services and to 

ecosystems per se.

2.1.3 Concepts of value

People assign or hold all values. All values, regardless 

of how they are defined, reflect either explicitly or 

implicitly what the people assigning them care about. In 

addition, values can be defined only relative to a given 

individual or group. The value of an ecological change 

to one individual might be very different than its value to 

someone else. 

Value is not a single, simple concept. People have 

material, moral, spiritual, aesthetic, and other interests, 

all of which can affect their thoughts, attitudes, and 

actions toward nature in general and, more specifically, 

toward ecosystems and the services they provide. Thus, 

when people talk about environmental values, the 

value of nature, or the values of ecological systems and 

services, they may have different things in mind that can 

relate to these different sources of value. Furthermore, 

experts trained in different disciplines (e.g., decision 

science, ecology, economics, philosophy, psychology) 

understand the concept of value in different ways. These 

differences create challenges for ecological valuations 

that seek to draw from and integrate insights from 

multiple disciplines.7

A fundamental distinction can be made between those 

things that are valued as ends or goals and those things 

that are valued as means. To value something as a means 

is to value it for its usefulness in helping bring about 

an end or goal that is valued in its own right. Things or 

actions valued for their usefulness as means are said to 

have instrumental value. Alternatively, something can be 

valued for its own sake as an independent end or goal. 

While a possible goal is maximizing human well-being, 

one could envision a range of other possible social goals 

or ends including protecting biodiversity, sustainability, 

or protecting the health of children. Things valued as 

ends are sometimes said to have intrinsic value. This 

term has been used extensively in the philosophical 

literature but there is not general agreement on its exact 

definition.8

 

Ecosystems can be valued both as independent ends 

or goals and as instrumental means to other ends or 

goals. This report therefore uses the term “value” broadly 

to include both values that stem from contributions 

to human well-being and values that reflect other 

considerations, such as social and civil norms (including 

rights), and moral and spiritual beliefs and commitments. 

The broad definition of value used here extends beyond 

what are sometimes called the benefits derived from 

ecosystem services. Even the term “benefits,” however, 

means different things in different contexts. In some 

contexts (e.g., Millennium Ecosystem Assessment Board, 

2003; Millennium Ecosystem Assessment, 2005), benefits 

refers to the contributions of ecosystem services to 

human well-being. In contrast, the term has a very precise 

meaning in the context of EPA regulatory impact analyses 

conducted under guidance from the U.S. Office of 

Management and Budget (OMB). In that context, benefits 

are defined by the economic concept of the willingness 

to pay for a good or service or willingness to accept 

compensation for its loss. 

Given the many ways in which people think about 

value, the committee discussed a number of different 

concepts of value. Table 1 lists the various concepts 

of value considered by the committee, categorized as 

either preference-based or biophysical. Although people 

assign or hold all values, preference-based values reflect 

individuals’ preferences across a variety of goods and 

services, including (but not limited to) ecosystems and 

their services. In contrast, biophysical values reflect 

contributions to explicit or implicit biophysical goals 

or standards determined to be important. The goal or 
14

standard might be chosen directly by decision makers 

or based on the preferences of the public or relevant 

groups of the public. Separating values into preference 

based and biophysical categories is not the only way 

to categorize values, but it has proven useful for the 

committee in understanding the various concepts of 

value used by different disciplines and how they are 

related.9

However, inclusion of a value concept on the list 

in table 1 does not imply a consensus endorsement 

by committee members of the use of that concept in 

ecological valuation. The task of distinguishing what 

is valued from the concept used to define the value is 

complex, regardless of the disciplinary perspective 

adopted. It requires clear, meaningful distinctions 

between the information available, perceptions of that 

information, and decisions or actions. Each discipline 

addresses these issues differently; these disciplinary 

differences are a potential source of confusion and 

miscommunication. So to make meaningful distinctions 

between these, the committee had to agree on a set 

of key assumptions. The resulting categorization of 

value concepts cannot be evaluated independent of 

these assumptions. Table 1 is not the only possible 

categorization. Rather it is the one that allowed the 

interdisciplinary C-VPESS to develop guidance relevant 

to EPA for valuing changes in ecosystem services.

The concepts of value listed in table 1 differ in a 

number of important ways. Attitude or judgment-based 

values are based on empirically derived descriptive 

theories of human attitudes, preferences, and behavior 

(e.g., Dietz et al., 2005). These values are not necessarily 

defined in terms of tradeoffs and are not typically 

constrained by income or prices, especially those that 

are outside the context of the specified assessment 

process. Rather, the values are derived from individuals’ 

judgments of relative importance, acceptability, or 

preferences across the array of changes in goods or 

services presented in the assessment. Preferences and 

judgments are often expressed through responses to 

surveys asking for choices, ratings, or other indicators of 

importance. The basis for judgments may be individual 

self-interest, community well-being, or accepted civic, 

ethical, or moral obligations. 

Economic values assume that individuals are 

rational and have well-defined and stable preferences 

over alternative outcomes, which are revealed through 

actual or stated choices (see, for example, Freeman, 

2003). Economic values are based on utilitarianism 

and assume substitutability, i.e., that different 

combinations of goods and services can lead to 

equivalent levels of utility for an individual (broadly 

defined to allow both self-interest and altruism). They 

are defined in terms of the tradeoffs that individuals are 

willing to make, given the constraints they face. The 

economic value of a change in one good (or service) 

can be defined as the amount of another good that an 

individual with a given income is willing to give up in 

order to get the change in the first good. Alternatively, 

it can be defined as the change in the amount of the 

second good that would compensate the individual to 

forego the change in the first good. Economic values 

can include both use and nonuse values, and they can 

be applied to both market and non-market goods.10

The tradeoffs that define economic values need not 

be defined in monetary terms (willingness to pay 

or willingness to accept monetary compensation), 

although typically they are. Expressing economic 

values in monetary terms allows a direct comparison 

of the economic values of ecosystem services with the 

economic values of other services produced through 

environmental policy changes (e.g., effects on human 

health) and with the costs of those policies. However, 

monetary measures of economic values should not be 

confused with other monetized measures of economic 

output, such as the contribution of a given sector or 

resource to gross domestic product (GDP).11

Community-based values are based on the 

assumption that, when consciously making choices 

about goods that might benefit the broader public, 

individuals make their choices based on what they think 

is good for society as a whole rather than what is good 

for them as individuals. In this case, individuals could 

place a positive value on a change that would reduce 

their own individual well-being (e.g., Jacobs, 1997; 

Costanza and Folke, 1997; Sagoff, 1998). In contrast to 

economic values, these values may not reflect tradeoffs 

that individuals are willing to make, given their income. 

Instead, an individual might express value in terms of 

the tradeoffs (perhaps, but not necessarily, in the form 

of monetary payment or compensation) that the person 

Preference-based values

 Attitudes or judgments

 Economic values

 Community-based values

 Constructed preferences

Biophysical values

 Bio-ecological values

 Energy-based values

Table 1: A classification of concepts of 

value as applied to ecological systems and 

their services.
feels society as a whole – rather than an individual – 

should be willing to make.

Values based on constructed preferences reflect the 

view that, particularly when confronted with unfamiliar 

choice problems, individuals do not have well-formed 

preferences and hence values. This view is based on 

conclusions that some researchers have drawn from 

a body of empirical work addressing this issue (e.g., 

Gregory and Slovic, 1997; Lichtenstein and Slovic, 

2006). It implies that simple statements of preferences 

or willingness to pay may be unstable (e.g., subject to 

preference reversals).12 Some have advocated using 

a structured or deliberative process as a way to help 

respondents construct their preferences and values (see 

section 5.1). This report refers to values arrived at by these 

processes as “constructed values.”The difference between 

economic values and constructed values can be likened 

to the difference between the work of an archeologist 

and that of an architect (Gregory et al., 1993). Economic 

values assume preferences exist and simply need to 

be “discovered” (implying the analyst works as a type 

of archeologist), while constructed values assume that 

preferences need to be built through the valuation process 

(similar to the work of an architect). As a result, the 

values expressed by individuals (or groups) engaged in a 

constructed-value process are expected to be influenced by 

the process itself. Constructed values can reflect both selfinterest and community-based values. 

Human preferences directly determine all of 

the concepts of value described above. In contrast, 

biophysical values do not depend directly on human 

preferences. Biophysical values reflect the contribution 

of ecological changes to a pre-specified biophysical 

goal or standard identified or set prior to measuring the 

contribution of those changes. This goal or standard 

can be defined in ecological terms (e.g., biodiversity or 

species preservation) or based on a biophysical theory of 

value (e.g., energy theory of value).

Bio-ecological values depend on known or assumed 

relationships between targeted ecosystem conditions and 

functions (e.g., biodiversity, biomass, energy transfer, 

and transformation), ecosystem functions, and the prespecified biophysical goal or standard (see Grossman and 

Comer, 2004). Scientists can determine bio-ecological 

values in several different ways that contribute to the 

goals. For example, contributions to a biodiversity goal 

could be based on individual measures such as genetic 

distance or species richness, or on more comprehensive 

measures that reflect multiple ecological considerations. 

Energy-based values are defined as the direct 

and indirect energy required to produce a marketed 

or un-marketed (e.g., ecological) good or service 

(see Costanza, 2004). In contrast to economic values, 

energy-based values are not defined in terms of the 

preference-based tradeoffs that individuals are willing 

to make, and hence the two concepts of value are 

conceptually distinct. Nonetheless, researchers who 

advocate the use of energy-based values have found 

that in some cases energy cost estimates are similar in 

magnitude to economic measures of value. Energy-based 

methods were designed to provide an alternative way 

to define value that is independent of short-term human 

preferences. However, some of the components used to 

construct these values depend on human choices and the 

preferences that underlie those choices.

The committee considered all of these various 

concepts of value in its deliberations. To date, EPA 

analyses have primarily sought to measure economic 

values, as required by some statutes and executive orders 

(see section 6.1). However, the committee believes that 

information based on other concepts of value can also 

be an important input into Agency decisions affecting 

ecosystems. Recognizing the significance of multiple 

concepts of value is an important first step in valuing the 

protection of ecological systems and services. 

2.1.4 The concept of valuation and different 

valuation methods

Because the committee’s charge relates to the value 

of protecting ecological systems and services, this 

report focuses on valuing ecological changes, rather 

than on valuing entire ecosystems or the broader 

question of assessing environmental values that relate 

to ecosystem protection.13 Thus, although ecosystems 

per se and their associated services have value, the term 

ecological valuation, as used here, refers to the process 

of measuring the value of a change in an ecosystem., 

its components, or the services it provides – i.e., it 

is predicated on a comparison of a given alternative 

scenario with a baseline scenario. In its simplest form, 

valuation requires, first, a prediction of a change in the 

ecosystem or the flow of ecosystem services, and then, 

the estimation of the value of that change. 

An important issue in ecological valuation is 

the extent to which individuals who express values 

understand the contributions of related ecological goods 

and services to human well-being. In many cases, an 

ecological change may have important implications 

that are not widely recognized or understood by the 

general public. This is particularly true for supporting or 

intermediate services, where the important contributions 

to human well-being are indirect. For example, 

Weslawski et al. (2004) indicated that the invertebrate 

fauna found in soils and sediments are important 

in remineralization, waste treatment, biological 

control, gas and climate regulation, and erosion and 

sedimentation control. However, the general public 

had no understanding or appreciation of these services 

(although the public may have an appreciation of the 

higher-level services or end-point services, such as 

clean water, aesthetics, and foods that could be derived 

from the system). Likewise, although individuals might 

15
16

understand the recreational contributions to human 

well-being associated with a given EPA action to limit 

nutrient pollution in streams and lakes, they might not 

recognize or fully appreciate the associated nutrientcycling or water-quality implications. If asked to value 

these services, they may express policy preferences or 

values that reflect incomplete information. Individuals 

might respond to a survey, make purchases, or otherwise 

behave as if they place no value on an ecosystem 

service if they are ignorant of the role of that service in 

contributing to their well-being or other goals.

There may be occasions where assessments of 

existing, uninformed attitudes and values held by the 

public are desired, such as when ascertaining current 

public understanding of particular ecosystems or 

services, and designing communications to improve 

understanding of ecosystems or services or to solicit 

public support for specific protection policies. In most 

cases, however, valuation should seek to measure the 

values that people hold and would express if they 

were well informed about the relevant ecological and 

human well-being factors involved. This embodies two 

principles. First, the ultimate objective of any valuation 

exercise is to assess the values of the public, not the 

personal values or preferences of scientists or experts. 

Basing valuation on the personal preferences of scientists 

or experts rather than those of the general public would 

undermine the usual presumptions that, in a democratic 

society, values held individually and collectively within 

society should be considered in public policy decisions, 

and that public involvement is central to democratic 

governance (e.g., Berelson, 1952; NRC, 1996).

Second, when EPA assesses values, the Agency 

should provide the public with as much of the relevant 

science as necessary to make informed judgments about 

the human/social consequences of the changes they 

are being asked to value. Lack of public understanding 

can pose a potentially serious challenge for ecological 

valuation. This problem can be reduced by explicitly 

incorporating into the valuation process information 

about ecological responses to policy options based 

on the best available science. For example, valuation 

exercises employing surveys should provide survey 

respondents with the relevant ecological information 

and the associated human/social consequences. 

Likewise, valuation exercises employing deliberative 

processes should convey relevant information directly to 

participants in the process. 

The lack of public understanding about underlying 

ecological functions and processes also highlights the 

importance of framing valuation-related questions in 

terms of services that people can directly understand 

and value (see further discussion in section 3.3.2). In 

many cases, this means asking people to value final or 

end services that directly affect them rather than asking 

them to value intermediate services whose effect is less 

direct. When an EPA action has an important effect on 

an intermediate service, it would then be incumbent on 

experts to predict the expected impact of these changes 

on final services, which could then be valued. In the 

example of Weslawski et al. (2004) discussed above, 

this would mean that individuals should not be asked to 

value a change in invertebrate fauna or the intermediate 

services they impact (remineralization, waste treatment, 

etc.). Rather, relevant science should be used to estimate 

how these changes would ultimately impact final services 

that individuals understand and appreciate (such as clean 

water, aesthetics, etc.), and the valuation questions should 

be framed in terms of these final services. 

Even when valuation is informed by the best available 

science, the valuation process will almost always involve 

uncertainty. Uncertainty arises in the prediction of 

changes in ecosystems, in the resulting change in the 

flow of services, and in estimating the values associated 

with those changes. The valuation process needs to 

recognize, assess, and communicate the various sources 

of uncertainty (see section 5.2 for further discussion). 

The valuation process should also recognize that 

information about different sources of value may be 

important for decision making, and it should identify 

appropriate methods to characterize or measure those 

values. There are a number of valuation methods that can 

be used to try to estimate or measure values. The methods 

considered here differ on a number of dimensions.

Perhaps most importantly, different methods can 

seek to measure different concepts of value, which 

differ in their theoretical foundations and assumptions. 

The committee engaged in considerable discussion and 

debate about the appropriate role of different methods. 

Although there is not a one-to-one mapping between 

valuation methods and the concepts of value discussed 

above, often different views about the appropriate role of 

alternative valuation methods stem from different views 

about the nature of value or the appropriate concept 

of value to apply in a given context. Researchers with 

different disciplinary backgrounds (e.g., economics, 

psychology, ecology, decision science) often adopt a 

particular concept of value and work primarily with and 

advocate a specific method or set of methods designed to 

measure that concept. 

For example, a fundamental distinction exists between 

valuation methods that assume individuals have welldefined preferences and those based on the premise 

that preferences – and hence values – are constructed 

through the valuation process. As discussed above, the 

concept of constructed values is based on the premise 

that, for complex and relatively unfamiliar goods such 

as ecosystems and some of their associated services, an 

individual’s preferences may not be well-formed and may 

be subject to intentional or unintentional manipulation or 

bias, for example by changes in the wording or framing 
17

of surveys (see “Survey issues for ecological valuation: 

Current best practices and recommendations for research 

“ at http://yosemite.epa.gov/Sab/Sabproduct.nsf/WebFiles/

SurveyMethods/$File/Survey_methods.pdf). The extent 

to which this is true has been the subject of scholarly 

debate both within the committee and outside, and 

most likely varies with the context (for different sides 

of this debate, see Becker and Stigler, 1967; Gregory, 

Lichtenstein and Slovic, 1993; Lichtenstein and Slovic, 

2006; and Tourangeau, 2000). If preferences and values 

regarding ecological systems and services are not wellformed and are instead constructed, they may not be 

accurately measured or characterized by valuation methods 

that assume well-formed preferences. For example, 

some individuals have strongly held values that they 

find difficult, impossible, or inappropriate to express in 

monetary units. Requiring these individuals to express 

such values in monetary equivalents (e.g., in a survey) may 

compel them to assume a perspective that is unfamiliar or 

even offensive. Valuation methods based on discourse and 

deliberation are designed to make explicit and facilitate the 

construction of preferences in such contexts. 

Methods differ along other dimensions as well. For 

example, they can differ in the type(s) of metrics or outputs 

produced. In addition, some valuation methods yield a 

single metric of value, while others yield multiple metrics. 

Methods that produce a single metric are not necessarily 

preferable to those that do not. Which approach is more 

appropriate or useful depends, in general, on the decision 

context. For example, if the context requires a ranking or 

choice based on a single criterion (e.g., net benefits), a 

valuation approach that yields a single (aggregate) metric 

is needed. In contrast, in a decision context where multiple 

values are involved (e.g., human health, threatened species, 

aesthetics, social equity, and other civil obligations) and 

decision makers themselves are charged with appropriately 

weighing and balancing competing interests and resolving 

trade-offs, a multi-attribute approach is preferable. 

Depending upon the context, this weighing and balancing 

might be done through political discourse or through a 

deliberative, decision-aiding process (see the discussions in 

section 5.3). 

Finally, some methods are well developed and have 

been applied extensively in different contexts; others 

are still evolving and require further development and 

testing. However, even for methods that have been used 

extensively in the past, applying these methods to value 

changes in ecological systems and services can pose 

significant challenges beyond those that might exist in 

other, less complex contexts. 

2.2 Ecological valuation at EPA

As noted in chapter 1, this report is focused on 

ecological valuation within EPA. This necessitates 

consideration of some issues that might not be 

considered in more general discussions of ecological 

valuation. EPA operates in a variety of different decision 

contexts where valuation might be useful. Although 

much of the interest in ecological valuation at EPA has 

focused on valuation needs in national rule making, 

valuation can also be useful in other decision contexts. 

Different parts of the Agency need valuation for different 

purposes and for different audiences. Some contexts 

closely prescribe how valuations are to be conducted; 

other contexts are less prescriptive. In addition, EPA 

faces institutional constraints that influence and limit 

how it typically conducts valuation in different contexts. 

This section of the report describes the committee’s 

understanding of the Agency’s needs and constraints 

related to ecological valuation. It then discusses the 

committee’s understanding of how ecological valuation 

is typically done at EPA, using an illustrative example. 

The committee’s observations from this example form 

the basis of its recommendations for an expanded 

and integrated approach to valuation discussed in the 

remainder of this report.

2.2.1 Policy contexts at EPA where ecological 

valuation can be important

As noted, much of the interest in ecological valuation 

at EPA stems from the need to better value the ecological 

effects of EPA actions in national rule makings. Two 

of EPA’s governing statutes (the Toxic Substances 

Control Act and the Federal Insecticide, Fungicide 

and Rodenticide Act) require economic assessments 

for national rule making. In addition, Executive 

Orders 12866 and 13422 have similar requirements 

for “significant regulatory actions.” These economic 

assessments provide information about whether the 

aggregate benefits of a policy or regulatory change 

exceed the costs, which is an important input into policy 

decisions (Arrow et al., 1996). An Office of Management 

and Budget circular on “Regulatory Analysis” (OMB 

Circular A-4) issued in September 2003 identifies key 

elements of a regulatory analysis for “economically 

significant rules.” Consistent with the principles of 

welfare economics that underlie benefit-cost analysis, 

the Circular defines benefits and costs in terms of 

economic values. Ecological valuation plays a key role 

in estimating or characterizing these values (see further 

discussions in sections 2.2.2 and 6.1.2).

EPA’s regional offices may also find valuation 

important in their partnerships with other governments 

and organizations where the contributions of ecological 

protection to human well-being are potentially important. 

Regional offices, for example, may find valuation 

useful in setting priorities, such as targeting projects for 

wetland restoration and enhancement, or in identifying 

critical ecosystems or ecological resources for attention. 

Valuation may also assist state and local governments, 

other federal agencies, and non-governmental 

organizations in deciding how best to protect lands and 

land uses and in communicating the suitability of the 
18

approach chosen. 

Valuation can also be useful to EPA in making 

site-specific decisions, such as those related to the 

remediation, restoration, and redevelopment of 

contaminated sites. By providing information about the 

value of the ecosystem services that could be obtained 

from site redevelopment, ecological valuation can 

improve decisions at cleanup sites, including hazardous 

waste sites listed on the Superfund National Priority List 

and other cleanup sites (e.g., sites that are the focus of 

EPA’s Brownfields Economic Redevelopment Initiative, 

Federal Facilities Restoration and Reuse Program, 

Underground Storage Tank Program, and Research 

Conservation and Recovery Act). 

Although many of the issues and recommendations 

throughout this report apply across decision contexts, 

specific valuation needs and opportunities vary across 

these contexts. For this reason, chapter 6 of this report 

discusses the implementation of the report’s general 

recommendations in these three specific decision 

contexts: national rule making, regional partnerships, 

and site-specific restoration or redevelopment. Other 

examples of contexts where ecological valuation may be 

useful for EPA include:

o Assessing programs as mandated by the Government 

Performance and Results Act (GPRA) of 199314

o Identifying Supplemental Environmental Projects 

(EPA Office of Enforcement and Compliance 

Assurance, 2001) for enforcement cases where 

projects involve protection of ecological systems 

and services

o Reviewing Environmental Impact Statements 

prepared by other federal agencies, under the 

National Environmental Protection Act

o Issuing permits to protect water quality for those 

specific states that have not applied for or been 

approved to run programs on their own and where 

established state water quality standards allow 

discretion to consider ecological valuation information. 

Although this report does not explicitly discuss these 

other contexts, the approach and selected valuation 

methods described can be useful in such contexts. 

2.2.2 Institutional and other issues affecting 

valuation at EPA

EPA must conduct ecological valuation within a 

set of institutional, legal, and practical constraints. 

These constraints include procedural requirements 

relating to timing and oversight, as well as resource 

limitations (both monetary and personnel). To better 

understand the implications of these issues for its work, 

the committee conducted a series of interviews with 

Agency staff.15 The interviews focused on the process 

of developing economic analyses as part of Regulatory 

Impact Assessments (RIA) for rule making and on the 

relationship between EPA and the Office of Management 

and Budget. The interviews also proved beneficial in 

better understanding strategic planning, performance 

reviews, regional analysis, and other situations where 

the Agency needs to assess the value of protecting 

ecosystems and ecosystem services.

EPA has a formal rule-development process 

involving several stages, each of which imposes 

demands on the Agency. Despite the rigidity of 

the process, Agency analysts assess the value of 

protecting ecosystems in different ways. Practices 

vary considerably across program offices, reflecting 

differences in mission, in-house expertise, and other 

factors. Program offices have different statutory and 

strategic missions and have primary responsibility 

for developing the rules within their mission-specific 

areas. The organization, financing, and skills of the 

program offices differ. Although the National Center 

for Environmental Economics (NCEE) is the Agency’s 

centralized reviewer of economic analysis within the 

Agency,16 the primary expertise and development of the 

rules resides within the program offices.

The timing of the process largely determines the kinds 

of analytical techniques that are employed. The timing is 

influenced by court-imposed deadlines on the rule process, 

as well as Paperwork Reduction Act requirements related 

to the collection and analysis of new data. By contrast, the 

scientific community is accustomed to much longer time 

horizons for their analyses. 

Collecting new data poses a significant bureaucratic 

problem for the Agency. To collect new information 

from individuals, businesses, and other entities protected 

under the Paperwork Reduction Act, the Agency must 

submit an Information Collection Request, which 

is reviewed within the Agency and by OMB. The 

Paperwork Reduction Act requires this hurdle and 

imposes the review responsibility on OMB, adding a 

significant amount of time to the assessment process. 

With a time limit of one or two years, at most, to conduct 

a study, this kind of review significantly limits the scope 

of analysis the Agency can conduct. Because EPA most 

often has not been able to collect new information, the 

Agency has, by necessity, relied heavily on transferring 

ecological and social values information from previous 

studies to new analyses.

OMB also acts as an oversight body to review EPA’s 

economic benefit analyses. EPA must justify its claims 

regarding the economic benefits of its actions, including 

any analyses of willingness to pay or willingness to 

accept for ecological protection. As noted above, OMB’s 

Circular A-4 provides explicit guidance for valuation. 

For a contribution to human welfare or cost that cannot 

be expressed in monetary terms, the circular instructs 

Agency staff to “try to measure it in terms of its physical 

units,” or, alternatively, to “describe the benefit or 
19

cost qualitatively” (p. 10).17 Thus, although Circular 

A-4 does not require that all economic benefits be 

monetized, it does require, at a minimum, some scientific 

characterization of those contributions. However, little 

guidance is provided on how to carry out this task. The 

circular instead urges regulators to “exercise professional 

judgment in identifying the importance of non-quantified 

factors and assess as best you can how they might 

change the ranking of alternatives based on estimated net 

benefits” (p. 10). 

In conducting benefit assessments, EPA has an 

incentive to use valuation methods that have been accepted 

by OMB in the past. This may create a bias toward 

the status quo and a disincentive to explore innovative 

approaches, both when monetizing values using economic 

valuation and when quantifying or characterizing values 

that are not monetized. The committee recognizes the 

importance of consistency in the methods used for 

valuation, but also sees limitations from relying solely 

on previously accepted methods when innovative or 

expanded approaches might also be considered. 

A related issue involves review of RIAs by external 

experts. The Agency does not take a standardized 

approach to RIA review. EPA staff and managers 

reported that peer review was focused only on “novel” 

elements of an analysis, meeting the requirements of 

EPA’s peer review policy (EPA, 2006d). This raises the 

question of how the term novel is defined by the Agency, 

and perhaps by OMB. More importantly, the novelty 

standard, ironically, creates another incentive to avoid 

conducting innovative analyses because the fastest, 

cheapest option is to avoid review altogether. 

Finally, the Agency relies, to varying degrees, on 

a variety of offices to develop assessments, including 

individual program offices and NCEE. It is not clear 

what form of organization is most effective. The 

Agency’s Ecological Benefits Assessment Strategic Plan 

(2006c) contains suggestions for addressing some of the 

limitations on ecological valuation resulting from the 

Agency’s internal structure. It advocates the creation of a 

high-level Agency oversight committee and a staff-level 

ecological valuation assessment forum. The committee 

endorses these recommendations. 

The Agency will continue to face significant external 

constraints when considering ecological valuation. 

The committee recognizes the practical importance 

of these constraints and advises the Agency to be as 

comprehensive as possible in its analyses within the 

limitations imposed by these constraints. 

2.2.3 An illustrative example of economic 

benefit assessment related to ecological 

protection at EPA

To better understand the current state of ecological 

valuation at EPA, the committee thoroughly examined one 

specific case in which assessment of economic benefits 

was undertaken: the environmental and economic benefits 

analysis that EPA prepared in support of new regulations 

for Concentrated Animal Feeding Operations (CAFOs) 

(EPA, 2002b).18,19 In communications with the committee, 

the Agency indicated that this analysis was illustrative in 

form and general content of other EPA regulatory analyses 

and assessments of the economic benefits of ecological 

protection. 

EPA proposed the new CAFO rule in December 2000 

under the federal Clean Water Act, to replace 25-yearold technology requirements and permit regulations. 

EPA published the final rule in December 2003. The 

new CAFO regulations, which cover more than 15,000 

large CAFO operations, require the reduction of manure 

and wastewater pollutants (from both feedlots and land 

applications of manure) and remove exemptions for 

stormwater-only discharges.

Because the proposed new CAFO rule constituted 

a significant regulatory action, Executive Order 12866 

required EPA to assess the economic costs and benefits 

of the rule. An intra-agency team at EPA, including 

economists and environmental scientists, worked with 

the U.S. Department of Agriculture on the economic 

benefit assessment. Before publishing the draft CAFO 

rule in December 2000, EPA spent two years preparing 

an initial assessment of the economic costs and 

benefits of the major options. After releasing the draft 

rule, EPA spent another year collecting data, taking 

public comments, and preparing assessments of new 

options. EPA published its final assessment in 2003. 

EPA estimates that it spent approximately $1 million 

in overall contract support to develop the assessment, 

with approximately $250,000 to $300,000 allocated to 

water-quality modeling.

EPA identified a wide variety of potential “use” 

and “non-use” benefits as part of its analysis.20 Using 

various economic valuation methods, EPA provided 

monetary quantifications for seven benefit categories.21 

Approximately 85 percent of the estimated monetary 

benefits quantified by EPA were attributed to 

recreational benefits. According to Agency staff, EPA’s 

analysis was driven by what EPA could monetize. EPA 

focused on those contributions for which data were 

known to be available for quantification of both the 

baseline condition and the likely changes stemming 

from the proposed rule, and for translation of those 

changes into monetary equivalents. 

EPA’s final assessment provides only a brief 

discussion of the contributions to human welfare that it 

could not monetize. A table in the Executive Summary 

lists a variety of non-monetized contributions 22 but 

designated them only as “not monetized.” EPA did not 

quantify these “contributions” in non-monetary terms 

(e.g., using biophysical metrics) or present a qualitative 

analysis of their importance. Instead, it represented 
20

the aggregate effect of these “substantial additional 

environmental benefits” simply by attaching a “+B” 

placeholder to the estimated range of total monetized 

benefits. Although the Executive Summary gives a 

brief description of these “non-monetized” benefits, the 

remainder of the report devotes little attention to them.

The CAFO economic benefits assessment illustrates 

a number of limitations in the current state of ecological 

valuation at EPA. First, as noted above, the CAFO 

analysis did not provide the full characterization 

of ecological contributions to human welfare using 

quantitative and qualitative information, as OMB 

Circular A-4 would appear to require. The report instead 

focused on a limited set of economic benefits, driven 

primarily by the ability to monetize these benefits using 

generally accepted models and existing value measures.23

These benefits did not include all of the major ecological 

contributions to human welfare that the new CAFO rule 

would likely generate.24 The circular requires that an 

assessment identify and characterize all of the important 

benefits of a proposed rule, not simply those that can 

be monetized. In this case, the monetized benefits alone 

exceeded the cost of the rule and hence the focus on 

benefits that could be readily monetized did not affect 

the outcome of the regulatory review. However, in a 

different context an economic benefit assessment based 

only on easily monetized benefits could inadvertently 

undermine support for a rule that would be justified 

based on a more inclusive characterization of 

contributions to human welfare. 

Second, the monetary values for many of the 

economic benefits were estimated through highly 

leveraged benefits transfers (transferring benefits derived 

from one or more study sites to a policy site) that often 

were based on dated studies conducted in contexts quite 

different from the CAFO rule application.25 This was 

undoubtedly driven to a large extent by time, data, and 

resource constraints, which made it very difficult for the 

Agency to conduct new surveys or studies and virtually 

forced the Agency to develop benefit assessments using 

existing value estimates. Nonetheless, reliance on dated 

studies in quite different contexts raises questions about 

the credibility or validity of the benefit estimates. This 

is particularly true when values are presented as point 

estimates, without adequate recognition of uncertainty 

and data quality.

Third, EPA apparently did not develop a comprehensive 

conceptual model of the rule’s potentially significant 

ecological effects. The report presents a simple 

conceptual model that traces outputs (a list of pollutants 

in manure – Exhibit 2-2 in the CAFO report) through 

pathways (Exhibit 2-1) to environmental and human 

health effects. 26 This model provided useful guidance, 

but was not sufficiently comprehensive to assure 

identification of all possible significant ecological 

effects. A conceptual model of the relevant ecosystem(s) 

at the start of a valuation project, as discussed in section 

3.1, can help to identify not only important primary 

effects but also important secondary effects – which 

frequently may be of greater consequence or value than 

the primary effects.27

Fourth, the CAFO analysis demonstrates the 

challenges of conducting required economic benefit 

assessments of ecological protection at the national 

level.28 National rule making inevitably requires EPA 

to generalize away from geographic specifics, in terms 

of both ecological responses to policy options and 

associated values. It is, however, possible (and desirable) 

to use existing and ongoing research at local and regional 

scales to conduct intensive case studies (e.g., individual 

watersheds, lakes, streams, estuaries) in support of the 

national-scale analyses. Systematically performing 

and documenting comparisons to intensive study sites 

can indicate the extent to which certain regions or 

conditions might yield impacts that vary considerably 

from the central tendency predicted by the national 

model. Alternatively, with sufficient data about the joint 

distribution of ecological, socio-economic, and other 

relevant conditions, case study results can be combined 

in a “bottom-up” approach to produce a national level 

analysis (see further discussion in section 6.1.3.1).

Fifth, although EPA invited public comment on the 

draft CAFO analysis as required by Executive Order 

12866, there is no indication in the draft CAFO report 

that the Agency consulted with the public for help in 

identifying, assessing, and prioritizing the effects and 

values addressed in its analysis. Nor is there discussion 

in the final CAFO analysis of any public comments that 

might have been received on the draft CAFO analysis. 

Early public involvement can play a valuable role 

in helping the Agency to identify all of the systems 

and services affected by proposed regulations and to 

determine the regulatory effects that are likely to be of 

greatest value. 

Sixth, EPA did not conduct a peer review of the 

benefit estimates used in the analysis of the CAFO rule. 

While the Agency appropriately emphasized peer review 

in its analysis and report, EPA did not seek peer review 

in deriving benefit estimates for the CAFO rule. Once 

again, this shortcoming is undoubtedly a function of 

time and resource constraints. However, peer review, 

especially early in the process, could help EPA staff 

identify relevant and available data, models, and methods 

to support its valuation efforts. An effective method 

would be to review not only individual components of an 

analysis (e.g., watershed modeling, air dispersal, human 

health, recreation, and aesthetics) but also the overall 

conceptual model and analytic scheme as well. 

Finally, EPA’s analysis and report closely adhered to 

the requirements of Executive Order 12866. Although 

the Executive Order provided the proximate reason 
21

for preparing the analysis and report, the Agency did 

not have to limit itself to the goals and requirements 

contained therein. The Executive Order does not 

preclude EPA from adopting broader goals and hence 

conducting other analyses in addition to the required 

benefit-cost analysis. Assessments such as the CAFO 

study can serve many purposes, including helping to 

educate policy makers and the public more generally 

about the economic benefits and other values that 

stem from EPA regulations. It is important for EPA to 

recognize this broader purpose. 

2.3 An integrated and expanded 

approach to ecological valuation: 

key features

The CAFO example highlights a number of 

limitations to the current state of ecological valuation at 

EPA. The committee’s analysis points to the need for an 

expanded, integrated approach to valuing the ecological 

effects of EPA actions. This approach focuses on the 

effects of greatest concern to people and on integrating 

ecological analysis with valuation. The remainder of this 

chapter describes the approach to ecological valuation 

developed and endorsed by the committee. The approach 

should serve as a guide to EPA staff as they conduct 

RIAs and seek to implement Circular A-4, as well as in 

decisions on regional and local priorities and activities. 

Subsequent chapters provide a more detailed discussion 

of the implementation of the approach. 

As noted above (see section 2.1.4), ecological 

valuation requires both prediction of ecological changes 

and an estimation of the value of those changes. 

The committee recommends that, when conducting 

ecological valuation, the Agency use a valuation process 

that has three key, interrelated features: 

o Early consideration of effects that are socially 

important

o Prediction of ecological responses in value-relevant 

terms

o Consideration of the possible use of a wider 

range of valuation methods to provide information 

about values

2.3.1 Early consideration of effects that are 

socially important

The first key component of the proposed approach is 

the early identification and prediction of the ecological 

responses that contribute to human well-being and are 

likely to be of greatest importance to people, whether 

or not the contributions are easily measured, monetized, 

or widely recognized by the public. These could 

include ecosystem responses that people value directly 

or the resulting responses in the services provided by 

the ecosystem. The importance of a given response 

will depend on both the magnitude and biophysical 

importance of the effect and on the resulting importance 

to society. Early in the valuation process EPA needs 

to obtain information about the ecosystem services or 

characteristics that are of greatest concern, so that efforts 

to quantify and characterize values can focus on the 

related ecological response. 

Identifying socially relevant effects requires a 

systematic consideration of the many possible sources of 

value from ecosystem protection and an identification of 

the values that may be relevant to the particular policy 

under consideration. Such a systematic consideration 

will likely expand the types of services to be 

characterized, quantified, or explicitly valued. Previous 

valuation assessments have often focused on what can 

be measured relatively easily, rather than what is most 

important to society. This can diminish the relevance, 

usefulness, and impact of the assessment. 

An obvious question is how to assess the likely 

importance of different ecological responses prior 

to completion of the valuation process. A main 

purpose of a thorough valuation study is to provide an 

assessment of the importance of ecological responses 

to different policy options. Nonetheless, in the early 

stages of the process, preliminary indicators of likely 

importance can serve as screening devices to provide 

guidance on the types of responses that are likely 

to be of greatest concern. EPA can obtain relevant 

information in a variety of ways. These range from indepth studies of people’s mental models and how their 

preferences are shaped by their conceptualization of 

ecosystems and ecological services, to more standard 

survey responses from prior or purpose-specific 

studies. In addition, early public involvement29 or 

the use of focus groups or workshops, composed of 

representative individuals from the affected population 

and relevant scientific experts, can help identify 

ecological responses of concern. 

In identifying what matters to people, it is important 

to bear in mind that people’s preferences depend on their 

understandings of causal processes and relationships and 

the information at hand. As noted previously, people’s 

expressions of what is important or of the tradeoffs they 

are willing to make can change with the amount and 

kind of information provided, as well as the manner in 

which it is conveyed. Collaborative interaction between 

analysts and public representatives can help to ensure 

that respondents have sufficient information when 

expressing views and preferences. In fact, EPA can 

use the ecological valuation process as a mechanism 

for increasing and augmenting public discourse about 

ecosystem services and how EPA actions affect those 

services, thereby narrowing the gap between expert and 

public knowledge of ecological effects.

The committee’s approach to valuation envisions 

consideration of a broader set of ecological effects. 

However, the committee recognizes that in most cases 
22

the purpose of the ecological valuation is to help answer 

specific questions that the Agency faces. The analyses 

do not always have to be complete to provide the 

information needed to answer a particular question. For 

example, suppose a state agency partnering with EPA 

must decide whether to allow logging at a particular site 

and an analysis focused solely on the recreational value 

of the unharvested site shows that these values alone 

exceed the net commercial value of logging. The agency 

can then conclude that logging will lead to a net social 

loss without valuing other ecological effects of logging. 

Thus, if the sole purpose of the valuation exercise is to 

determine whether the logging would generate a net 

social gain or loss and that determination can be based 

on a subset of values, then it would be unnecessary 

to expend a large effort to analyze the full suite of 

values. Of course, if the recreation value is less than 

the net commercial value of logging, the agency cannot 

conclude that logging would lead to a net social gain. 

In such cases, the analysis can be reframed to provide a 

lower bound on the magnitude of the ecological benefits 

from reduced logging that would be necessary to justify 

the cost. 

2.3.2 Predicting ecological responses in 

value-relevant terms

The second major component of the C-VPESS process 

is to predict ecological responses in terms relevant for 

valuation. This should begin with a conceptual model, 

followed by quantification (where possible) using specific 

ecological and related models. It requires both the 

prediction of biophysical responses to EPA actions and 

the mapping of those responses into effects on ecosystem 

services or features that are of direct concern to people 

– first conceptually, and then quantitatively. Ideally, this 

would be done using an ecological production function 

that is specified and parameterized for the ecosystem and 

associated services of relevance.

Numerous mathematical models of ecological 

processes and functions are available. These models 

cover the spectrum of biological organization and 

ecological hierarchy (e.g., individual level, population 

level, community level, ecosystem level, landscape level, 

and global biosphere). In principle, models can provide 

quantitative predictions of ecological responses to a 

given EPA action at different temporal and spatial levels. 

Some models are appropriate for specific contexts, such 

as particular species or geographic location, while others 

are more general. 

Ecological models provide a basis for estimating 

the ecological changes that could result from a given 

EPA action or policy (e.g., changes in net primary 

productivity or tree growth) and the associated changes 

in ecosystems or ecosystem services. However, many 

have been developed to satisfy specific research 

objectives and not EPA policy or regulatory objectives. 

Using these models to assess the contributions of EPA 

actions to human well-being thus poses challenges. 

The first challenge is to link existing models with 

Agency actions that are intended to control chemical, 

physical, and biological sources of stress. The valuation 

framework outlined here requires estimation of the 

biophysical responses to a specific EPA action. To be 

used for this purpose, ecological models must be linked 

to information about stressors. This link is often not a 

key feature of ecological models developed for research 

purposes. Existing models may need to be modified or 

new models developed to address this need.

Ecological models also need to be appropriately 

parameterized for use in policy analysis. Numerous 

ecological studies have been conducted at various levels, 

for example, at Long-Term Ecological Research Sites 

(Farber et al., 2006). These might provide a starting 

point for parameterizing policy-relevant models. A 

key challenge is to determine whether and to what 

extent parameters estimated from a given study site 

or population can be transferred for use in evaluating 

ecological changes at a different location, time, or 

scale. In many cases, data do not currently exist to 

parameterize existing models for use in assessing EPA’s 

actions. Such data may need to be developed before 

the Agency can use these models fully. To the extent 

that transferable models and parameter estimates exist, 

a central repository for this information would be 

extremely valuable.

The final, but perhaps most important, challenge 

is translating the responses predicted by standard 

ecological models into responses in terms of ecosystem 

services or features that can then be valued. If adapted 

properly, ecological models can connect material outputs 

to stocks and service flows (assuming that the services 

have been well-identified). Providing the link between 

material outputs and services involves several steps. 

These steps include: identifying service providers; 

determining the aspects of ecological community 

structure that influence function; assessing the key 

environmental factors that influence the provision of 

services; and measuring the spatial and temporal scales 

over which services are provided (Kremen, 2005). 

However, most ecological models currently are not 

designed with this objective in mind. In particular, they 

do not predict biophysical responses to stressors in ways 

that the public can understand or that directly link to 

human/social consequences that can be valued.

2.3.3 Use of a wider range of valuation methods

Given predicted ecological responses, the value of 

these responses needs to be characterized and, when 

possible, measured or quantified. As noted above, a 

variety of valuation methods exist. To date, economic 

valuation methods have been the mainstay of ecological 

valuation at EPA, not only in the context of national rule 

making (as required by OMB Circular A-4) but also in 
23

decision contexts not governed by OMB guidance. A key 

tenet of the valuation process proposed by the committee 

is consideration of both economic valuation methods and 

other valuation methods.

The committee sees two possible roles that use of a 

broader suite of methods might play. First, the use of an 

expanded suite of methods could allow EPA analyses to 

better capture the full range of contributions stemming 

from ecosystem protection and the multiple sources 

of value derived from ecosystems. Different valuation 

methods are designed to assess different sources of 

value, using different value concepts, and no single 

method captures them all. Thus, in contexts where the 

Agency seeks to capture all sources of value and is not 

constrained in this regard by legislative or executive 

rules, consideration of a broader suite of methods 

can contribute to this goal. The specific method(s) to 

be used would depend upon the underlying sources 

and concepts of value the Agency seeks to assess, 

as well as the specific information needs, legal and 

regulatory requirements (if any), data availability, and 

methodological limitations it faces. When the Agency 

can select from a range of methods, there may be scope 

for piloting and evaluating the use of methods that are 

relatively novel and in the developmental stage. 

Second, even when the Agency is required or chooses 

to base its assessment on economic values (for example, 

in the context of national rule making), non-economic 

valuation methods may be useful in supporting and 

improving the economic valuation (benefit assessment) 

in the following ways:

o Non-economic methods could help identify the 

ecological responses that people care about. For 

example, surveys, interviews, or focus groups in 

which individuals indicate the importance of different 

environmental and other concerns might provide 

information about the ecological effects of a specific 

rule that are likely to be viewed as important.

o Some non-economic methods could provide an 

indicator of an economic benefit that the Agency cannot 

monetize using economic valuation. For example, 

metrics that are primarily biophysical or socialeconomic indicators of impact, such as acres of habitat 

restored or the number and characteristics of individuals 

or communities affected, can serve as indicators of 

at least some contributions of ecosystem protection 

to human welfare (see further discussion in section 

6.1). As noted earlier, OMB Circular A-4 requires that 

benefits be quantified when they cannot be monetized; 

some bio-ecological or attitude/judgment-based metrics 

provide potentially useful forms of quantification in 

such circumstances. Although they would not provide 

full information about the magnitude of benefits, they 

might be expected to correlate with benefits. Thus, 

when properly chosen, higher levels of a particular 

biophysical, socio-economic or attitudinal metric would 

signal higher benefits.

o Non-economic methods could be used to provide 

supplemental information outside the strict benefitcost analysis about sources of value that might not 

be fully captured in benefit measures that come from 

economic valuation, such as moral or spiritual values. 

This is consistent with the EPA’s call in its Ecological 

Benefits Assessment Strategic Plan for exploring 

supplemental approaches to valuation. Even if not 

part of a formal benefit-cost analysis, information 

about non-economic values may be useful to both 

EPA and the public. 

Regardless of the specific role played by different 

methods, the use of a broader suite of methods must 

adhere to some fundamental principles. First, only 

valuation methods that meet appropriate validity and 

related criteria should ultimately be used. Section 4.1 

provides a discussion of criteria for assessing validity. 

The validity of some methods has already been subjected 

to considerable scrutiny. For methods that are still in 

the developmental stage, exploration of the method’s 

potential should include an assessment of the validity of 

the method using a scientifically based set of criteria.

The second principle relates to aggregation across 

methods. Clearly, values cannot be aggregated across 

methods that yield value estimates in different units. 

However, even when units are comparable (e.g., both 

methods yield monetary estimates of value), aggregation 

across methods may not be appropriate. Because of their 

different assumptions, different methods can measure 

quite different underlying concepts of value and hence 

yield measures that are not comparable. As a result, simple 

aggregation across methods is generally not scientifically 

justified. For example, it would be conceptually 

inconsistent to add monetary value estimates obtained from 

an economic valuation method and monetary estimates 

obtained from a deliberative process in which preferences 

are constructed, because the two are not based on the 

same underlying premises. Nonetheless, information 

about both estimates of value may be of interest to policy 

makers. In such cases, value estimates should be reported 

separately rather than aggregated across methods (see 

further discussion in section 6.1.3.1.). This is consistent 

with the suggestion above that, in the context of national 

rule makings where benefit assessments are conducted 

under Circular A-4, information about non-economic 

values should be considered separately (as supplemental 

information) rather than “added to” the economic benefit 

estimates to obtain a measure of total value. 

A third principle relates to the potential for doublecounting when multiple methods are used to measure 

or characterize values. Even when different valuation 

methods seek to measure the same underlying concept 

of value (so that aggregation is conceptually justified), 
24

adding estimates from different valuation methods could 

lead to double counting. This can arise either when the 

value of a change in a given final service is captured 

by multiple methods, or when both an intermediate 

service and the final service to which it contributes are 

valued separately. Clearly identifying which sources of 

value are captured by a given method (and which are 

not) will highlight any potential overlap that might exist 

when multiple methods are used. This could reduce the 

likelihood of double-counting.

2.4 Steps in implementing the proposed 

approach 

The previous section provides an overview of 

an integrated and expanded approach to ecological 

valuation proposed by the committee. The process for 

implementing the proposed framework would involve 

the following steps, depicted in figure 1. The six 

steps are:

1. Formulate the valuation problem and choose policy 

options to be considered, given the policy context

2. Identify the significant biophysical responses that 

could result from the different options

3. Identify the responses in the ecosystem and its 

services that are socially important

4. Predict the responses in the ecosystem and relevant 

ecosystem services in biophysical terms that link to 

human/social consequences and hence to values

5. Characterize, represent, or measure the value of 

responses in the ecosystem and its relevant services in 

monetary or non-monetary terms

6. Communicate results to policy makers for use in 

policy decisions

Although the steps are depicted sequentially, in 

actual practice numerous feedbacks should occur with 

interactions and iterations across steps. For this reason 

and other reasons (see section 3.1), it is important 

that the valuation process be based on a conceptual 

model, developed initially in steps 2 and 3, that can be 

updated and revised. For example, information about 

the value of responses in ecosystem services to a given 

set of policy options might cause a reformulation of 

the problem or identification of new policy options 

that could be considered. Also, a projected biophysical 

effect might suggest human-social values that were not 

initially considered. 

As depicted in figure 1, the implementation of the 

approach is also contingent upon the specific policy 

context and intended to provide input for a particular 

policy decision. As noted above, ecological valuation can 

play a key role in a number of different decision contexts, 

including national rule making and regional or local 

Figure 1: Process for implementing an expanded and integrated approach to ecological valuation

Policy

Decision Policy

context

Social, Behavioral, Economic, and Ecological Sciences

(1) Problem 

formulation/

generation of 

policy options

(2) Identification of 

potential ecological 

responses to options

(3) Identification of 

socially important 

assessment endpoints

(4) Prediction of ecosystem and 

ecosystem responses in biophysical 

terms

(5) Characterization, 

representation, or 

measurement of the 

value of changes in 

monetary and nonmonetary terms

(6) 

Communication 

of valuation 

results and 

integration with 

other analyses 

and inputs 

needed for 

decision
25

decisions regarding priorities and actions. The valuation 

problem should be formulated within the specific EPA 

decision context. Different contexts will generally be 

governed by different laws, principles, mandates, and 

public concerns. These contexts can differ not only in the 

required scale for the analysis (e.g., national vs. local) 

but possibly also in the type of valuation information 

that may be needed. For example, in contexts requiring 

an economic benefit-cost analysis, benefits need to be 

monetized whenever possible. In contrast, expressing 

contributions to human welfare in monetary terms might 

be of little or no relevance to EPA analysts in other 

contexts. The policy context therefore influences the 

appropriateness of methods, models, and data.

Figure 1 also highlights the need for information and 

input from a wide range of disciplines at each step of the 

process, beginning with problem formulation and the 

identification of the ecosystem responses that matter and 

continuing through the valuation of those responses. Instead 

of ecologists working independently from economists and 

other social scientists, experts in those disciplines should 

collaborate throughout. Ecological models need to be 

developed, modified, or extended to provide usable inputs 

for value assessments. Likewise, valuation methods and 

models need to be developed, modified, or extended to 

address important ecological and biophysical effects that 

may be underrepresented in value assessments. 

Figure 1 suggests a structure that in many ways 

parallels the Agency’s Framework for Ecological Risk 

Assessment (EPA Risk Assessment Forum, 1992; 

EPA Risk Assessment Forum, 1998). This framework 

underlies the ecological risk guidelines developed by 

EPA to support decision making intended to protect 

ecological resources (EPA Risk Assessment Forum, 

1992). Ecological valuation is a complement to 

ecological risk assessment. Both processes begin with 

an EPA decision or policy context requiring information 

about ecological effects. Next follows a formulation of 

the problem and an identification of the purpose and 

objectives of the analysis, as well as the policy options 

that will be considered. In addition, both ecological 

risk assessment and ecological valuation involve 

the prediction and estimation of possible ecological 

responses to an EPA action or decision. They also both 

ultimately use this (and related) information in the 

evaluation of alternative actions or decisions. 

Although they are similar, ecological valuation goes 

beyond ecological risk assessment in an important way. 

Typically, risk assessments primarily focus on predicting 

the magnitudes and likelihoods of possible adverse 

effects on species, populations, and locations, but do 

not provide information about the societal importance 

or significance of these effects. In contrast, ecological 

valuation seeks to characterize the importance to society 

of predicted ecological effects by providing information 

on either the value that society places on ecological 

improvements or the loss it experiences from ecological 

degradation. By incorporating human values, ecological 

valuation is closer to risk characterization than risk 

assessment. Many of the principles that should govern 

risk characterization outlined in the 1996 National 

Research Council Report Understanding Risk: Informing 

Decisions in a Democratic Society pertain to ecological 

valuation as well. For example, both should be the 

outcome of an analytical and transparent process that 

incorporates both scientific information and information 

from the various interested and affected parties about 

their concerns and values. 

2.5 Conclusions and recommendations 

Ecosystems provide a wide array of services that 

directly or indirectly support or enhance human 

populations. People also can value them in their own 

right for reasons stemming from ethical, spiritual, 

cultural, or biocentric principles. EPA’s broad mission to 

protect human health and the environment includes the 

protection of ecosystems. 

Many EPA actions affect the state of ecosystems 

and the services derived from them. To date, ecological 

valuation at EPA has focused primarily on a limited set 

of contributions to human well-being from ecological 

protection. This stems primarily from the difficulty 

of predicting the responses of ecological systems and 

services to EPA actions and the difficulty of quantifying, 

measuring, or characterizing the resulting contributions 

to human well-being and associated values. The 

presumption that contributions need to be monetized in 

order to be carefully characterized also restricts the range 

of ecological effects that are typically considered in EPA 

analyses, particularly at the national level. 

To implement the key features of an integrated an 

expanded approach to ecological valuation described 

in section 2.3 and reiterated in Table 2, the committee 

recommends that the Agency take the following steps. 

o EPA should cover an expanded range of important 

ecological effects and human considerations using an 

integrated approach. Such an approach should:

	 • Involve, from the beginning and throughout, an

interdisciplinary collaboration among natural and 

social scientists, as well as input about public 

concerns.

	 • Identify early in the process the ecological responses

or contributions to human well-being that are likely 

to be of greatest importance to people and focus 

valuation efforts on these responses. This would 

likely expand the range of ecological responses that 

are valued, recognizing the many sources of value.

	 • Predict ecological responses to EPA actions or

decisions in value-relevant terms. To do so, the 

valuation process should highlight the concept of 
26

ecosystem services and provide a mapping from 

responses in ecological systems to responses in 

services or ecosystem components that can be 

directly valued by the public.

	 • Consider the use of a wider range of possible

valuation methods, Methods not currently used by 

EPA could be used to provide information about 

multiple sources and concepts of value that might be 

of interest to the Agency and the public. In addition, 

they could contribute to assessments based on 

economic values by (a) helping to identify early in 

the process the ecosystem services that are likely to 

be of concern to the public and that should therefore 

be the focus of the assessment, and (b) addressing the 

requirement in Circular A-4 to provide quantitative 

or qualitative information about the possible 

magnitude of benefits (or costs) when they cannot be 

monetized using economic valuation. 

o Because EPA has limited experience with the use 

of non-economic valuation methods and some of 

these methods are still in the developmental stages, 

the committee believes that it would be wise for the 

Agency to pilot and evaluate the use of these other 

methods in different valuation contexts. In the context 

of national rule making, the Agency should conduct 

one or two model analyses (perhaps one prospective 

and one retrospective) of how the use of a wider 

range of methods could improve benefit assessments 

in the ways described above. This experience could 

then guide the Agency’s valuation efforts when it 

conducts subsequent benefit assessments. In addition, 

the Agency should pilot the use of other valuation 

methods in local and regional decision contexts, 

which are less prescriptive and therefore do not need 

to focus primarily on economic values. 

	 • As part of this effort, EPA should identify the

additional information to be collected and the 

valuation methods to be used to collect it. After the 

information is collected and the related valuation 

completed, EPA should evaluate the contribution of 

the data collected through the use of new methods to 

the overall valuation analysis. This evaluation should 

examine: (a) the properties of the method using 

a set of explicit criteria (see section 4.1); (b) the 

contribution of the new information to the decision 

process; and (c) the potential for using the new 

information in subsequent analyses (for example, as 

part of a value transfer). 

o EPA should create an institutional structure to 

facilitate consistent implementation of the proposed 

valuation approach across the Agency, including the 

establishment of a high-level oversight body and a 

staff-level valuation assessment forum, as suggested 

in the Agency’s Ecological Benefits Assessment 

Strategic Plan (EPA 2006c).

Through the use of the expanded and integrated 

valuation framework recommended in this report, 

EPA can move toward greater recognition and 

consideration of the effects that its actions have 

on ecosystems and the services they provide. This 

will allow EPA to improve environmental decision 

making at the national, regional, and site-specific 

levels and contribute to EPA’s overall mission 

regarding ecosystem protection. EPA can also better 

use the ecological valuation process to educate the 

public about the role of ecosystems and the value 

of ecosystem protection. Through this expanded 

and integrated approach, different publics can 

provide EPA with information about how they value 

ecosystem services. 

The remainder of this report discusses in more detail 

how to implement the ideas embodied in the C-VPESS 

integrated value assessment approach. Some of these 

ideas can be implemented in the short run, using the 

Early consideration of effects that are 

socially important

Prediction of ecological responses in valuerelevant terms

Consideration of the possible use of a wider 

range of valuation methods to provide 

information about values

Table 2: Key features of an expanded and 

integrated approach to valuation
27

existing knowledge base, while others require investments 

in research and data or method development. Specific 

recommendations regarding implementation and research 

needs are included in the chapters that follow. B
28

Chapter 2 presented an overview of an integrated and 

expanded approach to valuing ecological responses to 

EPA actions or decisions. This chapter focuses on one 

part of that approach: predicting ecological responses 

in value-relevant terms. In every context where the need 

for valuation arises, information about the magnitude 

of ecological effects will be a key component of value 

assessment. No matter what valuation method is used, 

the valuation process first requires an assessment of the 

responses of ecosystems and ecosystem services to the 

relevant EPA action or decision. Even where valuation 

is not possible, an assessment of these responses can 

provide valuable information to decision makers and the 

public. OMB in Circular A-4, for example, provides that, 

where a benefit cannot be expressed in monetary terms 

for a major national rule making, EPA “should still try to 

measure the benefit in its physical units.” 

This chapter begins with a discussion of the importance 

of developing an initial conceptual model of the relevant 

ecosystem and its services that can guide the entire 

valuation process. Section 3.2 discusses the steps needed to 

estimate the response of ecosystem and ecosystem services 

to EPA actions or decisions, including the key importance 

of ecological production functions. Section 3.3 highlights 

the challenges that currently exist in trying to implement 

ecological production functions in specific contexts. 

These challenges include understanding and modeling 

the relevant ecology, identifying the relevant ecosystem 

services, and mapping ecological responses into changes 

in the relevant ecosystem services. To a large extent, these 

challenges stem from the site-specificity and underlying 

complexity of ecosystems. Ecological responses to 

stressors are often non-linear and discontinuous. Section 

3.4 discusses the strategies for evaluating the effects 

of EPA actions on ecosystem services in the absence 

of a comprehensive ecological production function. 

Section 3.5 examines the problem of data availability 

and conditions where transfer of ecological information 

might be appropriate. Section 3.6 briefly addresses the 

importance of new ecological research to support valuation 

efforts. Finally, section 3.7 summarizes the committee’s 

conclusions and recommendations.

3.1 The road map: a conceptual model

The key first step in predicting the effects of EPA 

actions and decisions on ecological systems and services 

is the formulation of a conceptual model of the relevant 

ecosystem(s) and its associated services that can guide 

the valuation effort. The committee recommends that 

EPA start each ecological valuation by developing such a 

model. Because the purpose of the model is to guide the 

valuation process, the model should be context-specific 

and constructed at a general level. The conceptual 

model should diagram the predicted relationships 

among the relevant EPA actions, affected ecosystems, 

and associated services. The conceptual model is 

fundamentally a tool to help characterize and predict the 

ecological and social consequences of the relevant EPA 

actions and thereby help guide the full valuation process.

Later in the valuation process, EPA will need to use 

ecological production functions to generate more detailed 

analyses of key interactions, specific ecological responses 

to EPA decisions or actions, and resulting consequences to 

ecosystem services using ecological production functions. 

As discussed in section 3.3, these analyses will typically 

require the use of appropriately scaled and parameterized 

ecological models with a narrower focus. The conceptual 

model provides a framework for planning for the use of 

these predictive models at the start of the process and for 

integrating the more specific analyses into the overall 

valuation exercise. The goal in the development and use of 

all models should be to generate information of relevance to 

the policy making decision facing EPA (Dietz et al., 2003).

The conceptual model should clearly identify 

the relevant functional levels of the ecosystem, the 

interrelationships among ecosystem components, and 

how they contribute to the provision of ecosystem 

services, either directly or indirectly. Figure 2 provides 

an example illustrating some aspects of ecosystem 

services related to nutrient pollution, adapted from 

Covich et al. (2004). 

As figure 2 highlights, the conceptual model should 

include both information about the underlying ecology 

and a link to ecological services that are of importance 

to society. The conceptual model, for example, should 

include: the impacts of environmental stressors, such as 

waste disposal, on organisms at different trophic levels; 

key interactions among species at different levels; and 

changes at different levels that affect ecological services, 

such as the food supply, clean water, or recreation.

3

Building a foundation for ecological valuation: 

predicting ecological responses in valuerelevant terms
29

Figure 2: Illustration from Covich et al. (2004) showing relationships of major functional types to 

ecological services

Nutrient Loading

(e.g., weathering of soils)

fish, waterfowl, and other aquatic vertebrates

invertebrate predators

macroinvertebrate

grazers filter/deposit feeders shredders

Food Supply

Clean Water

(drinking water, irrigation)

Recreation

(e.g., hunting, fishing, boating)

FPOM

phytobenthos,

biofilms,

aquatic plants

protozoans

flagellates phyto- and

bacterioplankton

dissolved nutrients

Waste

Disposal

Terrestrial Input

of Organic Matter

fragmentation

leakage

(fine particulate organic matter)

Not surprisingly, ecologists often focus on 

underlying ecological relationships (depicted in the 

lower part of figure 2), and valuation experts tend 

to focus on the later, value-oriented stages of the 

process, starting with ecosystem services (shown at 

the top of the figure). A key principle of this report is 

the need to consider and integrate both aspects of the 

process. For ecological valuation aimed at improved 

decision making, a detailed analysis of ecological 

responses is insufficient unless those responses are 

mapped to responses in ecosystem services or system 

components that can be valued. Valuation exercises 

that do not reflect the key ecological processes and 

functions are similarly insufficient. Both parts of the 

valuation process are essential. The development 

of a conceptual model at the outset of the valuation 

process can help ensure that the process is guided by 

this basic principle.
30

The development of the conceptual model is a 

significant task that deserves the attention of EPA staff 

throughout the Agency, experts in relevant topics from 

the biophysical and social sciences, and the public. 

Involving all constituents, including the public, at this 

stage will enhance transparency, provide the opportunity 

for more input and better understanding, and ultimately 

give the process greater legitimacy. Participatory 

methods such as mediated modeling, described in 

section 5.3, can play a valuable role in the development 

of the conceptual model. To promote transparency 

and understanding, the conceptual model, the process 

for developing and completing it, and the decisions 

embedded in it should also be part of the formal record.

The conceptual model should allow for iteration 

and possible model changes and refinement over time. 

For example, analysts may initially believe that an 

action at a local site has local ecological effects, but, 

on further analysis of the stressors, realize that effects 

reach to more distant regions downstream or downwind, 

requiring a change in the conceptual model. Similarly, 

analysis of the relevant ecological system may show 

that stressors originally considered insignificant should 

be added to the conceptual model. As an example, a 

relatively non-toxic chemical effluent, normally seen as 

insignificant, might become significant if it is determined 

that low stream flows or intermittent streams effectively 

increase the concentration of the chemical to toxic levels 

during some parts of the year. The need for iterative 

model changes and refinements is critical and should be 

part of all valuation efforts. 

3.2 The important role of ecological 

production functions in implementing 

the conceptual model 

While the conceptual model serves as a guide 

for the overall valuation process, the individual 

components and linkages embodied in that model 

must be operationalized. The goal is to provide, to the 

extent possible, quantitative estimates of the responses 

of ecosystem components or services that can then be 

valued. Operationalizing the conceptual model requires 

mapping or describing: 

1. How the relevant EPA action will affect the ecosystem

2. How the effects on the ecosystem will, in turn, affect 

the provision of ecosystem services

3. How people value that ecosystem service response. 

The third step, valuation, is the subject of chapter 

4. The remainder of this chapter considers how to 

implement the first two steps, estimating how the EPA 

actions will affect the ecosystem, and how the ecosystem 

response will affect ecosystem services.

The first step requires describing how the EPA action 

– by reducing or eliminating a stressor or by otherwise 

protecting or altering an environmental factor – will affect 

important aspects of ecosystem structure or function. Would 

a stressor that EPA can eliminate otherwise cause a species 

to disappear or change in abundance? Would the stressor 

result in a change in biogeochemistry? For any important 

effects, EPA should make a quantitative estimate. 

The ecological production function is a critical tool 

for implementing the second step – estimating how 

the ecological response will affect the provision of 

ecosystem services. Ecological production functions are 

similar to the production functions used in economics 

to define the relationship between inputs (e.g., labor, 

capital equipment, raw materials) and outputs of goods 

and services. Ecological production functions describe 

the relationships between the structure and function of 

ecosystems, on the one hand, and the provision of various 

ecosystems services, on the other. These functions capture 

the biophysical relationships between ecological systems 

and the services they provide, as well as the inter-related 

processes and functions, such as sequestration, predation, 

and nutrient cycling. Coupled with information about 

how alternative EPA actions or management scenarios 

will affect the ecological inputs, ecological production 

functions can be used to predict the effects of the actions 

or scenarios on ecosystem services. 

Ecological production functions could describe 

the relationship between a broad suite of inputs and 

ecosystem services. An ecological production function 

could describe the relationship between inputs for 

an individual service or, to the extent that two or 

more services are linked (e.g., produced jointly or in 

competition), a multiple-output function could capture 

these linkages. 

The analogy between ecological production functions 

and economic production functions is not perfect. 

Economic production functions generally involve 

inputs over which humans have direct control, and the 

relationship between inputs and outputs is frequently 

well studied and defined. Ecological production 

functions, by contrast, involve inputs over which 

humans have variable and often limited control, and the 

relationship between inputs and outputs is complex and 

often very uncertain. Nonetheless, economic production 

functions provide a useful analogy for the type of 

relationships and models needed in order to effectively 

estimate the effect of EPA actions or scenarios on 

ecosystem services of importance to the public.

Scientists are making progress in understanding and 

defining ecological production functions for certain 

ecosystem services. One such service is pollination. 

Animal pollination is essential for the production 

globally of about one-third of agricultural crops and the 

majority of plant species (Kremen and Chaplin, 2007; 

Kremen et al., 2007). Ecologists have recently built 

spatially explicit models incorporating land use and its 
31

effect on habitat and foraging behavior of pollinators 

(Kremen et al., 2007). Such models can link changes 

in ecosystem conditions to the level of pollination of 

agricultural crops and their yields. Empirical studies 

using such models have shown the effects of proximity 

to natural forest on coffee productivity (Ricketts et al., 

2004) and the interaction of wild and honey bees on 

sunflower pollination (Greenleaf and Kremen, 2006). 

A second ecosystem service for which considerable 

progress has been made in developing ecological 

production functions is carbon sequestration. Agricultural 

systems, forests, and other ecosystems contain carbon in 

soil, roots, and above-ground biomass. Rapidly growing 

markets for carbon sequestration and the potential 

to generate carbon credits are pushing interest in the 

accurate assessment of the carbon sequestration potential 

of agricultural and other managed ecosystems (Willey 

and Chamaides, 2007). It is possible to quantify aboveground carbon stores fairly accurately in various types of 

ecosystems such as forests (e.g., Birdsey, 2006; Smith et 

al., 2006; EPA Office of Atmospheric Programs, 2005), 

but greater uncertainty remains about stocks of soil carbon 

that make up the majority of carbon in agricultural and 

grassland systems (e.g., Antle et al., 2002; EPA Office of 

Atmospheric Programs, 2005). 

Despite this progress, our current understanding of 

ecological production functions for most ecosystem 

services remains limited (Balmford et al., 2002; 

Millennium Ecosystem Assessment, 2005; NRC, 2004). 

Although many ecological models exist, most do not 

predict ecosystem service responses. The next section 

discusses some of the challenges in developing complete 

ecological production function models for use in 

ecological valuation. 

3.3 Challenges in implementing 

ecological production functions

Developing and implementing an ecological 

production function requires: 

o Characterizing the ecology of the system

o Identifying the ecosystem services of interest

o Developing a complete mapping from the structure 

and function of the ecological system to the provision 

of the relevant ecosystem services 

Figure 3 provides a graphical representation of the 

necessary elements of an ecological production function. 

On the left side of the figure, ecological models at 

various organizational levels predict ecological elements 

or attributes – ecological endpoints – that can be linked 

to ecosystem services of interest. These ecological 

Figure 3: Graphical depiction of ecological production functions

Habitable

Space

Foraging 

Area

Population Level

Biomass

Species

Biodiversity

Biogeochemical

Functions

Biosphere

Preservation

Eco-tourism

Clean Water

Harvest

Flood Control

Aesthetics

Ecological Models Ecological Endpoints Map to Ecosystem Services

ECOLOGICAL PRODUCTION FUNCTIONS

Ecological

Services

Individual

Level

Population 

Dynamic 

Level

Community

Level

Ecosystem

Level

Global

Level

Spiritual Value
32

models are important components of an ecological 

production function, but they are not the complete 

function. An ecological production function requires that 

the endpoints of these ecological models be mapped or 

translated into corresponding predictions regarding the 

ecosystem services of interest to humans.

Each of these three key steps in developing and 

implementing ecological production functions face 

challenges that EPA should work to address. This section 

elaborates on the challenges.

3.3.1 Understanding and modeling the 

underlying ecology 

As noted, the first step in developing an ecological 

production function is to understand the components, 

processes, and functioning of the ecosystem that underlie 

and generate the ecosystem services. Analysts must 

have a strong understanding of the underlying ecology. 

Although much is known about ecological systems, 

current knowledge is still very incomplete, largely 

because ecosystems are inherently complex, dynamic 

systems that vary greatly over time and space. 

As an example of the complexity of ecological 

functions, consider the ecological services associated 

with the activities of soil organisms that might be 

affected by disposal of waste on that soil. These 

organisms thrive on organic matter present or added 

to the soil. By breaking down that organic matter, 

certain groups of organisms maintain soil structure 

through their burrowing activities. These, in turn, 

provide pathways for the movement of water and air. 

Other kinds of organisms shred the organic material 

into smaller units that microbes then utilize. The 

microbes release nutrients in a form that higher plants 

can use for their growth or in a dissolved form that 

can move hydrologically from the immediate site into 

groundwater or a stream. Other groups of specialized 

microbes may release various nitrogen gases directly 

to the atmosphere. The nature of soil organisms and 

the products that they utilize, store, or release all help 

to regulate the biogeochemistry of the site, as well as 

the site’s hydrology, productivity, and carbon-storage 

capacity. Predicting the effect of particular actions on 

ecosystem services such as waste processing and the 

provision of clean water requires an understanding of 

these complex ecological relationships. 

Complexity also stems from the fact that ecological 

effects may persist for different periods of time, 

affecting both the temporal and spatial scales that are 

relevant for any analysis. The ecological effects from 

carbon dioxide in the atmosphere, for example, are 

likely to persist far longer and require a larger temporal 

and spatial analysis than the effects from acute toxic 

exposures to hazardous chemicals. 

Because of the complexity of most ecosystems, 

analysts need ecological models to organize information, 

elicit the interactions among the variables represented 

in the models, and reveal outcomes under different 

sets of assumptions or driving variables. Some models 

are statistical; others are primarily simulation models. 

Some statistical and theoretical models are relatively 

small, containing a few equations. Other ecological 

models are very large, involving hundreds of interacting 

calculations. Models may be valuable in many of the 

steps of assessing ecological value including: 

o Estimating stress loading

o Estimating the exposure pattern of stress (especially 

the spatial and temporal implications)

o Identifying ecological elements receiving exposure

o Estimating the exposure-response function of 

ecological elements

o Estimating the change in stress from potential 

Agency actions

o Estimating the response of ecosystem services or 

functions to change in stress

Ecological models can describe ecological systems 

and ecological relationships that range in scale from 

local (individual plants) to regional (crop productivity) 

to national (continental migration of large animals). 

These models frequently focus on specific ecological 

characteristics, such as the populations of one or 

more species or the movement of nutrients through 

ecosystems, and can cover the full spectrum of biological 

organization and ecological hierarchy. For instance, a 

hydrological model might describe possible changes in 

the timing and amount of water in streams and rivers. A 

biogeochemical model might predict effects on the levels 

of various chemical elements in soils, groundwater, and 

surface waters. A terrestrial carbon cycle model might 

project changes in plant growth and in carbon sinks 

or sources. Population and community models might 

project changes in specific animal and plant populations 

of concern. 

Inevitably, models suffer from limitations. Although 

many ecological models are well established and used 

routinely for describing ecological systems, ecological 

models can only represent the current state of knowledge 

about the dynamics of an ecological system and generate 

outputs only as reliable as the data the models use. The 

dynamism of a system adds to the challenge of modeling, 

as do the non-linear and discontinuous responses of 

system components. The model outputs are subject to 

known, and sometimes unknown, levels of statistical 

uncertainty. Chapter 5 of this report discusses the issue of 

uncertainty and how EPA should address uncertainty in 

its valuation efforts (section 5.2.2 examines the specific 

sources of uncertainty in ecological valuations.) It is 

important that EPA assess and report on all sources 

of uncertainty in order to permit a more informed 

evaluation of and comparison between policy options. 
33

At the moment, the important point to emphasize is 

that uncertainty pervades the entire valuation process, 

including the modeling of ecological processes.

Moreover, no ecological model can include all 

possible interactions. Some ecological models explicitly 

or implicitly incorporate human dimensions, but most 

focus primarily on ecological functions. In addition, 

models capture historical relationships and typically 

are not able to predict ecosystem patterns for which no 

modern counterpart exists. For example, if a stressor 

such as climate change leads species to “reshuffle into 

novel ecosystems unknown today” for which there is no 

analog, current models will not predict the effect (Fox, 

2007; Dasgupta and Maler, 2004). 

Data insufficiency also frequently constrains 

the applicability, and to some degree formulation, 

of ecological models. Even when a full theoretical 

model of an ecosystem exists, applying the model to 

a specific context of interest will require determining 

the parameters of the model for that context. However, 

parameterization is generally difficult because of the 

complexity of ecological systems and their dependence 

on an array of site-specific variables. As a result, many 

ecological models are site specific. The relatively large 

amounts of site-specific data required to build and 

parameterize models mean that transferability of the 

models is limited, either because the model has been 

developed using spatially constrained data or because 

inadequate data are available at specific sites with which 

to drive or parameterize the model. This site-specificity 

can significantly limit models’ applicability to the spatial 

and temporal complexities required in valuing ecosystem 

services, especially at regional and national scales. 

Ecological models incorporate the best available 

scientific knowledge of how ecosystems will respond 

to a given perturbation and the sensitivity of various 

ecosystem components. The committee therefore 

recommends that EPA support all of its ecological 

valuations with ecological models and data sufficient to 

understand and estimate the likely ecological response to 

major alternatives being considered by decision makers. 

Ecological models are essential in representing and 

analyzing ecological production functions. Guided by the 

conceptual model described in section 3.1, the Agency 

should use ecological models to quantify the likely 

effects of an action on the ecosystem and the resulting 

effect on ecosystem services. 

Given the limitations of many current models, 

however, the committee also recommends that EPA make 

the development of effective ecological models one of 

its research priorities. EPA is already strengthening its 

approach for developing and using models for decision 

making. For example, EPA has established the Council 

for Regulatory Environmental Modeling (CREM), a 

cross-Agency council of senior managers with the goal 

of improving the quality, consistency, and transparency 

of models used by the Agency for environmental decision 

making. The committee endorses this effort and advises 

EPA to continue to strengthen its work in this area. 

Because many ecological models exist and a variety 

of models might be used for any particular valuation 

context (Roughgarden, 1998b), the Agency will often 

be faced with a choice among one or more predictive 

models. The appropriate choice of models, and the 

availability and appropriateness of supporting databases, 

will depend in part on the scale of analysis (e.g., local vs. 

national) and the precision of the analysis needed for the 

relevant policy decision. 

The committee recommends that EPA identify 

clear criteria for selecting ecological models and apply 

these criteria in a consistent and transparent way. 

Several existing reports discuss the selection and use 

of models for environmental decision making and can 

provide valuable guidance to EPA in the valuation 

context. In 2005, EPA’s Council for Regulatory 

Environmental Modeling prepared a “Draft Guidance 

on the Development, Evaluation and Application of 

Regulatory Environmental Models.” In 2006, an EPA 

Science Advisory Board panel reviewed the draft report 

and provided recommendations on revisions (EPA 

Science Advisory Board, 2006a). Until EPA publishes 

final guidance, the draft guidance and SAB review can 

provide EPA with valuable advice in selecting models. 

A 2007 report of the National Research Council Board 

on Environmental Studies and Toxicology entitled 

“Models in Regulatory Environmental Regulatory 

Decision Making” also provides valuable guidance 

on selecting appropriate ecological models for use in 

valuation exercises. The criteria in these reports and 

the SAB review can guide the Agency both in selecting 

among models and in setting priorities for future model 

development. 

These reports address environmental modeling in 

general and do not focus on the use of ecological models 

for valuation purposes. For valuation purposes, EPA 

should use the criteria from these reports and choose 

models that generate outputs either directly in terms of 

relevant ecosystem services or that are easily translatable 

into effects on such services. The ultimate goal is to 

provide a measure of the value of the effects of an action 

on ecosystem services. The models chosen must advance 

that goal.

3.3.2 Identifying ecosystem services

Another key challenge in implementing ecological 

production functions is identifying the relevant 

ecosystem services to be evaluated in any given context. 

As already emphasized, ecological production functions 

must ultimately link ecological responses to effects on 

ecosystem services. This requires that EPA identify the 

relevant services in a consistent and appropriate way. 
34

Identifying the relevant ecosystem services cannot be 

done deductively. The relevant services depend on what 

is important to people in the specific context, once they 

have been informed about potential ecological effects. 

The objective is to identify what in nature matters to 

people and to express this intuitively and in terms that 

can be commonly understood. Technical expressions or 

descriptions meaningful only to experts are not sufficient; 

however, underlying ecological science must inform the 

identification of relevant services. Identifying relevant 

services requires a collaborative interaction among 

ecologists, social scientists, and the public. 

The Millennium Ecosystem Assessment (2005) 

provides a good starting point for identifying potentially 

relevant ecosystem services by providing an extensive 

discussion and classification of ecosystem services. In 

each specific context, however, EPA should also seek 

input from the general public and from individuals 

or entities particularly affected by the relevant EPA 

decision as to what is important. In doing so, EPA can 

use a variety of sources, such as the valuation methods 

described in chapter 4 (e.g., surveys, mental models 

research, or deliberative processes), content analysis 

of public comments, solicitation of expert opinion and 

testimony, and summaries of previous decisions in 

similar circumstances.

Moving toward a common understanding of 

ecosystem services is important for the success of 

future valuation efforts. The relative success of EPA 

efforts to translate air quality problems into human 

health-related social effects is due in part to the 

development of agreements about well-defined health 

outcomes that can be valued. In order to value the 

health effects of air pollution, it has been necessary 

to move from describing effects in terms such as 

oxygen transfer rates in the lung to terms that are 

more easily understood and valued by the public, such 

as asthma attacks. Although the search for common 

health outcomes that can be used for valuation has 

been difficult, the lesson is clear: If health and social 

scientists are to productively interact in assessing the 

value of improved environmental quality, measures 

of health outcomes that are understandable and 

meaningful to both groups of scientists are necessary. 

These outcomes are now understood by disciplines 

as divergent as pulmonary medicine and urban 

economics (EPA Science Advisory Board, 2002a). The 

search for common outcomes that can be valued will 

be equally important in the ecological realm, where 

biophysical processes and outcomes can be highly 

varied and complex. 

Some authors have advocated the development of 

a common list of services to be collectively debated, 

defined, and used by both ecologists and social scientists 

across contexts (e.g., Boyd and Banzaf, 2006). Such a 

list might include:

o Species populations – including those that generate 

use value, such as harvested species and pollinator 

species, and those that generate existence values

o Land cover types – such as forests, wetlands, natural 

land covers and vistas, beaches, open land, and 

wilderness

o Resource quantities – such as surface water and 

groundwater availability

o Resource quality – such as air quality, drinking water 

quality, and soil quality

o Biodiversity

Although only a subset of the services on a common 

list might be relevant in any particular context, the list 

would provide some standardization in the definition of 

ecosystem services across contexts. Advocates argue that 

development of a common list is the best way to debate 

and convey a shared mindset, foster the integration of 

biophysical and social approaches, and provide greater 

transparency, legitimacy, and public communication 

about what in nature is being gained and lost. Achieving 

agreement on a common list might be an important goal, 

but it is likely to be difficult for complex ecological 

systems. Converging prematurely on a limited list of 

services could misdirect valuation efforts and miss 

important intermediate and end services. 

To ensure that the services can be readily and 

accurately valued, the identification of relevant 

ecosystem services, either as a common list or for a 

specific analysis, should follow some basic principles. 

First, it is important to avoid double counting. All things 

that matter should be counted, but only once.30 Second, 

the ecosystem services should have concrete outcomes 

that can be clearly expressed in terms that the public can 

understand. If ecological outcomes are to provide useful 

input into valuation, they must be described in terms that 

are meaningful to those whose values are to be assessed. 

EPA has launched several initiatives to develop 

common and useful endpoints for ecological models. 

These endpoints, however, are typically not themselves 

ecosystem services. The endpoints instead are often 

ecological attributes or elements, such as biomass, that 

serve as inputs to the production of ecosystem services. 

Although these endpoints often link to the Agency’s 

statutory responsibilities and policy concerns, social 

scientists typically cannot use them by themselves to 

value effects on ecosystem services. Looking at figure 

3, social scientists need information on the ecosystem 

services at the right side of the diagram. Most endpoints, 

shown in the center column of figure 3, are at least one 

step removed and must still be translated into responses 

in ecosystem services.

EPA’s generic ecological assessment endpoints 

(GEAEs) (EPA Risk Assessment Forum, 2003) provide a 

valuable example. The GEAEs are based on legislative, 
35

policy, and regulatory mandates. If expanded to include 

landscape-, regional-, and global-level endpoints (see 

EPA Risk Assessment Forum, 2003, Table 4.1; Harwell 

et al., 1999; EPA Science Advisory Board 2002b), 

they can serve as a first step in characterizing relevant 

ecological systems and quantifying responses to 

stressors. Although the GEAEs are a valuable starting 

point, they also illustrate how far EPA must go in 

estimating responses in ecosystem services. First, the 

GEAEs are expressed in technical terms and not in terms 

of concrete outcomes that the public can understand. 

These technical terms are certainly appropriate for some 

regulatory purposes, but most of the public is unlikely to 

be familiar with them. Therefore, they will have limited 

use in valuation.

Second, the GEAEs do not necessarily reflect the 

things in nature that people care about. Although the 

endpoints reflect policy and regulatory needs (EPA Risk 

Assessment Forum, 2003, p.5), they depict a narrow 

range of ecological outcomes, confined to organism, 

population, and community or ecosystem effects. 

They do not relate to water availability, aesthetics, 

or air quality, but rather to kills, gross anomalies, 

survival, fecundity and growth, extirpation, abundance, 

production, and taxa richness. These effects are clearly 

relevant to biological assessment. However, for anglers 

who care about the abundance of healthy fish in a 

particular location at a particular time, lost value depends 

not on the number of kills or anomalies but rather on the 

abundance of healthy fish. 

Another important ecological endpoint initiative 

is EPA’s Environmental Monitoring and Assessment 

Program (EMAP). Created in the early 1990s, EMAP is 

a long-term program to assess the status and trends in 

ecological conditions at regional scales (Hunsaker and 

Carpenter 1990; Hunsaker, 1993; Lear and Chapman, 

1994). Once again, the endpoints developed in EMAP 

are generally not direct measures of ecosystem services. 

EMAP does, however, emphasize the importance of 

developing endpoints that are understandable and 

useful to decision makers and the public. As EPA 

has recognized, if an endpoint is to serve as a useful 

indicator of ecological health, it “must produce results 

that are clearly understood and accepted by scientists, 

policy makers, and the public” (Jackson et al., 2000). 

One study that used focus groups to examine the value of 

EMAP endpoints as indicators of environmental health 

similarly concluded that there is a need “to develop 

language that simultaneously fits within both scientists’ 

and nonscientists’ different frames of reference, such that 

resulting indicators [are] at once technically accurate and 

understandable” (Schiller et al., 2001). The committee 

agrees with this conclusion and urges EPA to move 

further toward this goal. 

The Agency is aware of the limitations of current 

endpoints. The committee emphasizes the limitations 

for two reasons: to highlight the difference between 

the Agency’s current approach to defining relevant 

ecological endpoints and the need to identify effects 

on ecosystem services; and to encourage the Agency to 

move toward identifying and developing measures of 

ecosystem services that are relevant and directly useful 

for valuation. 

The identification of relevant ecosystem services will 

require increased interaction between natural and social 

scientists within the Agency. The committee urges the 

Agency to foster this interaction through a dialogue 

related to the identification and development of measures 

of ecosystem services. One means of doing this is to 

encourage greater coordination among the Agency’s 

extramural research programs, including the DecisionMaking and Valuation for Environmental Policy grant 

program and the Office of Research and Development’s 

ecosystem-services research program. A joint research 

initiative focused on the development of measures of 

ecosystem services will address a critical policy need and 

provide a way for the Agency to integrate its ecological 

and social science expertise in a very concrete fashion.

3.3.3 Mapping from ecosystem responses to 

changes in ecosystem services

Once the underlying ecology is understood and 

modeled and the relevant ecosystem services are 

identified, ecological production functions still require 

a correlation of the ecosystem responses to the relevant 

ecosystem services. As noted above, although numerous 

ecological models exist for modeling ecological 

systems, most of them fall short of estimating effects 

on ecosystem services. Many of the models have been 

developed to satisfy research objectives, rather than 

Agency policy or regulatory objectives. The outputs of 

these models have not generally been cast in terms of 

direct concern to people and thus are not useful as inputs 

to valuation techniques. For example, evapotranspiration 

rates, rates of carbon turnover, and changes in leaf area 

are important for ecological understanding, but are not 

outputs of direct human importance. Some models exist 

with outputs directly related to human values and include 

models that predict fish and game populations or forest 

productivity. These models, however, address only a 

limited set of ecosystem services. 

3.4 Strategies to provide the ecological 

science to support valuation

Although development of a broad suite of ecological 

production functions faces numerous challenges, EPA 

can employ several other approaches at this time to 

gain a better understanding of how ecosystem services 

respond to its actions. These approaches include using 

indicators that are correlated with ecosystem services 

and using meta-analyses. Indicators represent a form of 

simplification; meta-analysis is based on information 

aggregation. 
36

3.4.1 Use of indicators 

As noted above, an ecological production function 

describes the relationship between ecological inputs 

and ecosystem services. When a full characterization 

of this relationship is not available, some indication of 

the direction and possible magnitude of the changes in 

the services that would result from an Agency action 

might still be obtained using indicators. “Indicators,” 

as the term is used here, are measures of key ecosystem 

properties whose changes are correlated with changes in 

ecosystem services.31 In general, an indicator approach 

involves selecting and measuring key predictive 

variables rather than defining and implementing a 

complete ecological production function. Because of 

the complexity of the interactions between economic 

and ecological systems, economists frequently take a 

similar simplified approach that focuses on effects only 

in the relevant markets, assuming that the effects on the 

broader market are negligible and can be ignored (Settle 

et al., 2002). 

Indicators can provide useful information about how 

ecological responses to EPA actions or decisions might 

affect ecosystem services. If it is known that an indicator 

is positively or negatively correlated with a specific 

ecosystem service, predicting the change in the indicator 

can provide at least a qualitative prediction of the change 

in the corresponding ecosystem service. Indicators may 

be important even where models exist that can provide 

more sophisticated ecological analysis. The use of 

large, complex ecological models to make numerous or 

rapid evaluations can be difficult, especially given the 

quantities of required data and the short time in which 

assessments generally must be made (Hoagland and 

Jin, 2006). In these situations, simplification can be far 

more practical. The use of indicators that simplify and 

synthesize underlying complexity can have advantages in 

terms of both generating and effectively communicating 

information about ecological effects. 

Ecologists and environmental scientists have sought 

to identify indicators of ecosystem condition that 

might be linked to specific services. Many ecosystem 

indicators have been proposed (NRC, 2000; EPA, 2002a; 

EPA, 2007a), and several states have sought to define 

a relatively small set of indicators of environmental 

quality. Indicator variables have been established for 

specific ecosystems such as streams (e.g., Karr, 1993) 

and for entire countries (e.g., The H. John Heinz III 

Center for Science, Economics, and the Environment, 

2008). The committee acknowledges EPA’s work in 

developing indicators for air, water, and land and for 

ecosystem condition and encourages the Agency to see 

where those indicators can be linked to specific services 

relevant to the valuation of EPA decisions.

There is currently no agreement on a common set of 

indicators that can be consistently applied and serves 

the needs of decision makers and researchers in all 

contexts (Carpenter et al., 2006). However, there are 

guidelines for specific issues. For example, in evaluating 

the economic consequences of species invasion, Leung 

et al. (2005) have developed a framework for rapid 

assessments based on indicators to guide in prevention 

and control, simplifying the ecological complexity to a 

relatively small number of easily estimated parameters. 

One potentially useful approach to indicators is 

to incorporate multiple dimensions into a coherent 

presentation that describes the status of ecosystems 

within a region, especially as the ecosystems relate to 

social values and ecosystem services. For example, 

“ecosystem report cards,” such as those developed for 

South Florida (Harwell et al., 1999) and for Chicago 

Wilderness (available at http://www.chicagowilderness.

org/pubprod/index.cfm ), use an array of indicators 

designed to provide information about the status 

and trends associated with the ecological services 

provided by the ecosystems. The report card 

identifies seven ecosystem characteristics thought to 

be important: habitat quality, integrity of the biotic 

community, ecological processes, water quality, 

hydrological system, disturbance regime (changes 

from natural variability), and sediment/soil quality. 

These characteristics are then related to the goals and 

objectives for the report card.32 The outputs are not 

quantitatively valued or monetized, but rather described 

by narratives or quantitative/qualitative grades that are 

scientifically credible and understandable by the public. 

The report card is designed to:

o Be understandable to multiple audiences

o Address differences in ecosystem responses 

across time

o Show the status of the ecosystem

o Transparently provide the scientific basis for the 

assigned grades on the report card

This simplified approach to ecological modeling 

cannot identify all the possible consequences of 

EPA actions. The challenge is building ever more 

complex models that address a wide array of issues 

over multiple spatial and temporal scales. It may well 

be that, with accumulated experience, it may be more 

practical to adopt the simplified approach of selecting 

a few key indicators or ecological processes that are 

correlated with specific ecosystem services and can 

be valued. The committee advises EPA to continue 

research to develop key indicators for use in ecological 

valuation. This is likely to be particularly fruitful 

when those indicators can be used for key repeated 

rule makings or other repeated decision contexts. 

Such indicators should meet ecological science and 

social science criteria for effectively simplifying 

and synthesizing underlying complexity while still 

providing scientifically based information about key 

ecosystem services that can be valued. Use of the 
37

chosen indicators should also be accompanied by an 

effective monitoring and reporting program.

3.4.2 Use of meta-analysis 

A second promising approach to providing information 

about effects on ecosystem services is the use of metaanalysis. Meta-analysis involves collecting data from 

multiple sources and attempting to draw out consistent 

patterns and relationships from those data about the links 

between ecological functions or structures and associated 

services. For example, Worm et al. (2006) attempted to 

measure the effects of biodiversity loss on ecosystem 

services across the global oceans. They combined 

available data from multiple sources, ranging from smallscale experiments to global fisheries. In these analyses, the 

impossibility of separating correlation and causation is a 

severe limitation. But examining data from site-specific 

studies, coastal regional analyses, and global catch 

databases allowed these researchers to draw correlative 

relationships between biodiversity and decreases in 

commercial fish populations – variables that can be valued 

and monetized.

In a similar approach, de Zwart et al. (2006) noted 

that ecological methods for measuring the magnitude 

of biological degradation in aquatic communities are 

well established (e.g., Karr, 1981; Karr and Chu, 1999.), 

but determining probable causes is usually left to a 

combination of expert opinion, multivariate statistics, 

and weighing of evidence. As a result, the results are 

difficult to interpret and communicate, particularly 

because mixtures of potentially toxic compounds are 

frequently part of these assessments. To address this 

issue the authors used a combination of ecological, 

ecotoxicological, and exposure modeling to provide 

statistical estimates of probable effects of different natural 

and anthropogenic stressors on fish. This approach links 

fish, habitat, and chemistry data collected from hundreds 

of sites in Ohio streams. It assesses biological conditions 

at each site and attributes any impairment (e.g., loss of 

one or more of 117 fish species) to multiple probable 

causes. When data were aggregated from throughout 

Ohio, 50 percent of the biological effect was associated 

with unknown factors and model error; the remaining 

50 percent was associated with alterations in stream 

chemistry and habitat. The technique combines multiple 

data sets and assessment models to arrive at estimates 

of the loss of fish species based on broad patterns. Like 

the Worm et al. (2006) study of the relationship of 

biodiversity to ocean productivity, this study aggregates 

data from many sources and uses various models to 

arrive at estimates that can be easily interpreted and, 

at least in the case of game fish species, valued and 

monetized. In a similar context, EPA’s Causal Analysis/

Diagnosis Decision Information System (CADDIS) 

permits scientists to access, share, and use environmental 

information to evaluate causes of biological effects found 

in aquatic systems (see http://cfpub.epa.gov/caddis).

3.5 Data availability 

Data availability is a serious problem in the 

development of ecological production functions. 

However, data on the structure and function of ecological 

systems are becoming more available and better 

organized across the country. Part of the increased 

availability is simply that Web-based publication now 

enables authors to make data and analysis readily 

available to other researchers in electronic format. 

Also, as government agencies are being held more 

accountable, these agencies are increasingly making the 

data they collect and use available to constituents. EPA’s 

National Water-Quality Assessment (NAWQA) program 

provides useful data on the nation’s waterways and 

aquatic systems in a consistent and comparable fashion 

(see http://water.usgs.gov/nawqa).

The committee recommends that EPA work with 

other agencies and scientific organizations, such as 

the National Science Foundation (NSF), to encourage 

the sharing of ecological data and the development of 

more consistent ecological measures that are useful for 

valuation purposes. EPA should also encourage strong 

regional initiatives to develop information needed for 

valuations. Within the ecological research community, 

the NSF’s Long-Term Ecological Research (LTER) 

program has emphasized organizing and sharing data 

in easily accessible electronic datasets. Although these 

data have rarely been collected for valuing ecosystem 

services, they measure long-term trends and therefore 

can be particularly valuable in separating short-term 

fluctuations from longer-term patterns in ecological 

conditions. Recently, the LTER program has focused on 

regionalization, in which data are collected from sites 

surrounding a primary site, providing a regional context 

for site-based measurements and models.33

EPA also can look to the social sciences for useful 

insights into the building of data-sharing capacity. The 

social sciences have a lengthy and successful history 

of sharing data through repositories such as the InterUniversity Consortium on Political and Social Research 

(www.icpsr.umich.edu).

3.5.1 Transferring ecological information from 

one site to another

Despite the increasing availability and organization 

of ecological data, there is rarely enough available 

information to support many desired analyses. In 

addition, the costs of collecting extensive data from 

all the sites in which EPA is considering action would 

be prohibitive. An important issue is the reliability of 

transferring ecological information from one site to 

another or over different spatial or temporal scales. 

The information can include tools or approaches, data 

on properties of an ecosystem or its components, and 

services or contributions to human well-being provided 

by an ecosystem. 
38

There are no hard and fast rules for when ecological 

information can be transferred. Confidence in doing so 

depends on the types of information and the systems 

in question. Given the complexity of most ecosystems, 

the richness of interactions, and the propensity for 

non-linearity, extrapolation of ecological information 

requires caution. However, certain generalizations are 

possible. Information is more likely to be transferable 

when there is greater similarity between ecosystem 

contexts. Also, aggregate information, such as data on 

ecosystem properties, is more likely to be transferable 

than information on particular species or the interactions 

of particular species. Thus, the ecosystem properties (e.g., 

leaf area index, primary productivity, or nitrogen-cycling 

patterns) of an oak-hickory deciduous forest in Tennessee 

might be transferable to oak-hickory forests in other parts 

of the eastern United States that are at similar stages of 

development. To a lesser extent, the information might be 

transferable to other types of deciduous forests.

Information may be transferable to other spatial or 

temporal scales if the dynamics over time and space 

are known for the ecosystems. For instance, if data are 

available on how the characteristics of an oak-hickory 

forest change as it develops or goes through cycles of 

disturbance, data transfers from one point in time to 

another should be possible. Similarly, if information is 

available on how the properties of the system vary with 

spatial environmental variation (e.g., local climate, soil 

type, or land-use history), the extension of information 

from one spatial context to another should be possible. 

EPA and other national and international agencies have 

sponsored extensive research on the scaling up of data 

from particular sites to regions (Suter, 2006, chapters 

6 and 28; Turner et al., 2007). The results from these 

analyses are applicable to the transfer of information on 

ecological properties and services.

To some extent, the same generalizations apply to 

transferring tools such as models, although success 

depends on how generally applicable the tool is and how 

difficult in terms of data requirements it is to parameterize 

for other situations. For example, forest ecosystem models 

can often be transferred to other forests using available 

information from sources such as LTER sites. 

3.6 Directions for ecological research to 

support valuation 

EPA has briefed the committee on its plans to 

redesign a major part of its intramural and extramural 

research program to forecast, quantify, and map 

production of ecosystem services (see briefings to 

the C-VPESS, EPA Science Advisory Board, 2006b 

and 2007b). The committee welcomes these efforts 

as a way to strengthen the foundation for ecological 

valuation. EPA should evaluate the validity of all models 

that it develops or uses to assess the reliability of the 

biophysical changes or responses that they predict.

The committee notes with concern EPA’s limited and 

shrinking resources for ecological research (EPA Science 

Advisory Board, 2007a). Although the committee has not 

received any details about Agency plans, it encourages 

the Agency to carefully focus its research program 

because the cost of implementing ecological production 

functions in multiple places on multiple issues may be 

significant. The committee commends EPA for asking 

for additional science advice on its Ecological Research 

Program Strategy and Multi-year Plan and believes this 

advisory activity should be a priority for an SAB panel 

of interdisciplinary experts in ecological valuation, 

drawing on information in this report.

3.7 Conclusions and recommendations

Implementation of the integrated valuation process 

recommended by this report requires the Agency to 

predict the ecological responses to its actions, identify 

the relevant ecosystem services of importance to the 

public, and link the predicted ecological responses to 

the effect on those services. Estimating the responses 

of relevant ecosystem services to EPA actions is an 

essential part of valuation and must be done before the 

value of those responses can be assessed. 

With regard to predicting the responses of 

ecosystems and ecosystem services, the committee 

recommends the following:

o EPA should begin each valuation with a conceptual 

model of the relevant ecosystem and the ecosystem 

services that it generates. This model should serve 

as a road map to guide the valuation. EPA should 

formalize a process for constructing the initial 

conceptual model, recognizing that the process must 

be iterative and respond to new information and 

multiple points of view. The conceptual model should 

reflect the ultimate goal of valuing the effect of EPA’s 

decision on ecosystems and ecosystem services. The 

model and its documentation should also clearly 

describe the reasons for decisions about the spatial 

and temporal scales of the chosen ecological system, 

the process used to identify stressors associated with 

the proposed EPA action, and the methods to be used 

in estimating the ecological effects. In constructing 

the conceptual model, the Agency should involve staff 

throughout EPA, as well as relevant outside experts 

from the biophysical and social sciences, and seek 

information about relevant public concerns and needs.

o EPA should identify and develop measures of 

ecosystem services that are relevant to and directly 

useful for valuation. This will require increased 

interaction between natural and social scientists 

within the Agency. In identifying and evaluating 

services for any specific valuation effort, EPA should 

describe them in terms that are meaningful and 

understandable to the public. 
39

o EPA should seek to use ecological production functions 

wherever practical to estimate how ecological responses 

(resulting from different policies or management 

decisions) will affect the provision of ecosystem 

services. (EPA Science Advisory Board 2008b).

o All ecological valuations conducted by EPA should 

be supported by ecological models and data sufficient 

to understand and estimate the likely ecological 

responses to major alternatives being considered by 

decision makers. There are many ecological models. 

Building on recent efforts within the Agency and 

elsewhere, EPA should develop criteria or guidelines 

for model selection that reflect the specific modeling 

needs of ecological valuation and apply these criteria 

in a consistent and transparent way. 

o Because of the complexity of developing and using 

complete ecological production functions, the 

committee advises EPA to continue and accelerate 

research to develop key indicators for use in 

ecological valuation. Such indicators should meet 

ecological and social science criteria for effectively 

simplifying and synthesizing underlying complexity 

and be associated with an effective monitoring and 

reporting program. The Agency can also advance 

ecological valuations by supporting the use of 

methods such as meta-analysis that are designed 

to provide general information about ecological 

relationships that can be applied in ecological 

valuation.

o EPA should work with other agencies and scientific 

organizations, such as the National Science 

Foundation, to encourage the sharing of ecological 

data and the development of more consistent 

ecological measures that are useful for valuation 

purposes. EPA should similarly encourage strong 

regional initiatives to develop information needed 

for valuations. EPA should also promote efforts 

to develop data that can be used to parameterize 

ecological models for site-specific analysis and 

case studies, or that can be transferred or scaled to 

other contexts. 

o EPA should carefully plan and actively pursue 

research to generate ecological production 

functions for valuation including research on 

ecological services and support for modeling and 

methods development by the Office of Research and 

Development and the Science to Achieve Results 

(STAR) program. It is a high priority to develop 

ecological models that can be used in valuation efforts 

and to evaluate the validity of those models.

o Finally, the committee advises the Agency to foster 

interaction between natural scientists and social 

scientists in identifying relevant ecosystem services 

and developing and implementing processes for 

measuring and valuing them. As part of this effort, 

EPA should more closely link its research programs 

on evaluating ecosystem services and valuing 

ecosystem services. B
40

4

Methods for assessing value

In advocating an expanded and integrated approach 

to valuing the protection of ecological systems and 

services, the committee urges the Agency to consider, 

pilot, and evaluate a broader set of valuation methods. 

This chapter provides an overview of the methods 

that the committee discussed for possible use in 

implementing its approach, including methods and 

approaches for transfer of valuation information.

As noted in chapter 2, the methods considered by 

the committee vary in the roles that they might play 

in different decision contexts. For example, as noted 

previously, benefit assessments for national rule makings 

must be conducted under the guidance of Office of 

Management and Budget Circular A-4, which implies 

that, in that context monetized valuations must be based 

on appropriate economic methods. Other valuation 

methods can still provide useful information in this 

context, but the role of these methods is limited by 

the need to follow the guidance in the circular (see 

sections 2.3.3 and 6.1). In other, less-prescribed decision 

contexts, non-economic valuation methods can play a 

larger role in analysis (see sections 6.2 and 6.3). Thus, 

as the Agency considers alternative methods that might 

be used, it must consider the context of the information 

needs defined by the particular policy context in which 

the valuation exercise will be done. 

4.1 Criteria for choosing valuation 

methods

The methods discussed by the committee differ in 

a number of important respects. These include: the 

underlying assumptions and concepts of value they 

seek to measure or characterize; the empirical and 

analytical techniques used to apply them; their data 

needs (inputs) and the metrics they generate (outputs); 

their involvement of the public; the degree to which the 

method has been developed or utilized; their potential 

for future use at EPA; and the issues involved in 

implementing the methods. 

Any method used by the Agency must meet relevant 

scientific standards. Before relying on any given method 

in a particular valuation process, EPA must determine 

if there is a scientific basis for the method’s use in 

that context. Methods that are in their early stages 

of development and application to valuation must be 

evaluated both for their scientific merit and for their 

appropriateness in the given context of interest. Methods 

that are well-developed, have been extensively used for 

valuation, and have been validated in other contexts 

should still be evaluated for their suitability in valuing 

ecosystems and services, because a given context may 

pose challenges that might not exist in other situations. 

In addition, when considering what methods to use 

in specific contexts, EPA should consider the specific 

policy objectives and whether a given method provides 

information relevant to that objective. For example, 

methods that focus on biophysical measures of value 

may be relevant for objectives defined solely in terms 

of biophysical criteria but less suitable when policy 

objectives are defined more broadly in terms of human 

well-being. In this latter case, methods that allow for 

consideration of not only ecosystem services but also the 

many other things that contribute to human well-being 

(e.g., human health) will be more suitable. 

The committee has not developed a full set of criteria 

for evaluating methods, nor has it applied criteria 

comprehensively to the methods discussed here. The 

committee advises EPA to develop criteria and evaluate 

methods by those criteria prior to use in valuation. This 

will assist the Agency not only in determining when 

methods are suitable but also in determining where to 

invest scarce resources. 

Some suggestions for criteria that EPA should 

consider for inclusion are described briefly in section 

4.1.1. In developing criteria for evaluating valuation 

methods, a distinction should be made between criteria 

for evaluating the suitability of a particular method in 

a given context (i.e., evaluating the scientific merit and 

suitability of the method) and criteria for evaluating 

the manner in which the method is actually applied 

(i.e., evaluating the implementation of the method). For 

example, the question of whether survey methods in 

general can appropriately be used to estimate or elicit 

value(s) in a particular context is a different question, 

requiring different criteria, than the question of whether 

a specific survey was properly designed and executed to 

estimate or elicit the intended value(s). If not properly 

implemented, any method can yield results that are 

not useful for the intended purpose. For any individual 

method, EPA can develop criteria to ensure that the 

method is carefully implemented. Criteria of this type 

exist for many of the methods described here, and 

committee members have described criteria for many 

valuation methods (see valuation method descriptions 

on the SAB Web site at http://yosemite.epa.gov/sab/

sabproduct.nsf/WebBOARD/C-VPESS_Web_Methods_

Draft?OpenDocument). The committee recommends that 

EPA develop a higher-order list of criteria designed to 

evaluate the suitability of specific methods for a specific 

valuation context, assuming that any method chosen 

would be implemented according to best practices.
41

4.1.1 Suggested criteria

While not prescribing the specific criteria that EPA 

should use to evaluate methods before using them in a 

specific context, the committee offers some suggested 

criteria. These draw on the literature cited below, as well 

as the committee’s own deliberations. 

A primary consideration in evaluating a method 

should be the extent to which the method seeks to elicit 

or measure a concept of value that has a consistent 

and transparent theoretical foundation appropriate 

for the intended use. Different valuation methods 

measure different concepts of value. For a method 

to be appropriate in a valuation context, it must seek 

to measure a concept of value that is well-defined, 

theoretically consistent, and relevant for the particular 

valuation context. For example, a method derived 

from a biodiversity-based theory of value would not 

be relevant in a context where biodiversity is not 

important. Similarly, legal requirements may prescribe 

a theory of value that must be used in a particular 

valuation context (most notably, national rule making). 

Thus, the Agency should consider the theory of value 

underlying a particular method and its relevance when 

evaluating the appropriateness of using that method in a 

specific context. 

Assuming a method seeks to elicit or measure a 

well-defined and relevant concept of value, another 

over-arching criterion for evaluation is validity – i.e., 

how well the method measures the underlying 

construct that it is intended to measure (Gregory et al., 

1993; Freeman, 2003; Fischhoff, 1997). Although the 

underlying construct of value is not directly observable, 

it can be estimated through the use of valid methods. 

EPA should use criteria to assess the extent to which a 

given method is likely to yield a measure, or at least an 

unbiased estimate, of the underlying construct of value. 

Examples of criteria that provide information about the 

validity of a method include:

o Does the method capture the critical features of the 

relevant population’s values, including how deeply 

they are held? Does it yield value estimates that 

reflect the intensity of people’s preferences or the 

magnitude of the contribution to a given goal?

o Does the method impose demands on respondents 

that limit their ability to articulate values in a 

meaningful way? For example, does the method 

impose unrealistic cognitive demands on individuals 

expressing values? Does it allow those individuals 

to engage in the process that they would normally 

undertake to identify or formulate and then articulate 

their values?

o Does the method yield value estimates for individuals 

that those individuals would, if asked, consent to have 

used in the proposed way? Fischhoff (2000) suggests 

that this form of implied informed consent can help 

to ensure the quality of valuation data generated by 

a given method and avoid inappropriate use of the 

resulting value estimates, by ensuring that individuals 

would “stand behind researchers’ interpretation of 

their responses” (p. 1439). This does not necessarily 

require that researchers using the method actually 

seek such consent. Rather, it provides a hypothetical 

benchmark that can be used in assessing whether a 

method is capturing what is intended.

o Does the method ensure that measured or elicited 

values reflect relevant scientific information? A 

basic premise of the valuation approach proposed 

by the committee is that a method should elicit or 

measure values that individuals would hold when 

well-informed about the relevant science. This does 

not require that all individuals expressing values 

know as much as scientific experts in the field, but 

rather that they understand as much of the science 

as necessary to make informed judgments about 

the service(s) they are being asked to value. For 

example, they should be aware of the magnitude of 

the changes in ecosystem services or characteristics 

that would result from the ecological changes being 

valued, as well as the implications of those changes 

for themselves and for others.

o Does the method yield value estimates that are 

responsive to changes in variables that the relevant 

theory suggests should be predictors of value, and 

invariant to changes in variables that are irrelevant to 

the determination of value? For example, under an 

economic theory of value, an increase in the quantity 
42

Table 3: Methods considered by the committee for possible use in valuation

Method Form of output/units Related concepts(s) of

value from table 1

Measures of attitudes, preferences, and intentions

Survey 

questions 

eliciting 

information 

about attitudes, 

preferences, and 

intentions

Attitude scales, preference or importance rankings, 

behavioral intentions toward depicted environments or 

conditions

Attitudes and judgments; 

community-based values

Individual 

narratives and 

focus groups

Qualitative summaries and assessments from transcripts Attitudes and judgments; 

community-based values

Behavioral 

observation

Inferences from observations of behavior by individuals 

interacting with actual or computer-simulated 

environments

Attitudes and judgments;

community-based values

Economic methods

Market-based 

methods

Monetary measure of willingness-to-pay (WTP) for 

ecosystem services that contribute to the provision of 

marketed goods and services

Economic value

Travel cost Monetary measure of WTP for ecosystem services that 

affect decisions to visit different locations

Economic value

Hedonic pricing Monetary measure of marginal WTP or willingness-toaccept (WTA) as revealed by price for houses or wages 

paid for jobs with different environmental characteristics

Economic value

Averting 

behavior

Monetary or other measure of WTP as revealed by 

responses to opportunities to avoid or reduce damages, 

for example, through expenditures on protective goods or 

substitutes

Economic value

Survey 

questions 

eliciting stated 

preferences

Monetary or other measures of WTP or WTA as 

expressed in survey questions about hypothetical 

tradeoffs

Economic value

Civic valuation

Referenda and 

initiatives

Rankings of alternative options, or monetary or other 

measure of tradeoffs a community is willing to make, as 

reflected in community choices

Community-based 

values; indicator of 

economic value under 

some conditions

Citizen valuation 

juries

Rankings of alternative options, or monetary or other 

measures of required payment or compensation, based 

on jury-determined assessments of public values

Community-based 

values; constructed 

values

Decision science approaches

Decision science 

approaches

Attribute weights that reflect tradeoffs individuals are 

willing to make across attributes, including ecological 

attributes, for use in assigning scores to alternative policy 

options

Constructed values
43

Table 3: Methods considered by the committee for possible use in valuation (continued)

Method Form of output/units Related concepts(s) of

value from table 1

Ecosystem benefit indicators

Ecosystem 

benefit 

indicators

Quantitative spatially-differentiated metrics or maps 

related to supply of or demand for ecosystem services

Indicators of economic 

value and/or communitybased values

Biophysical ranking methods

Conservation 

value method

Spatially-differentiated index of conservation values 

across a landscape

Bio-ecological value

Embodied 

energy analysis

Cost of the total (direct plus indirect) energy required to 

produce an ecological or economic good or service

Energy-based value

Ecological 

footprint

Area of an ecosystem (land and/or water) required to 

support a consumption pattern or population

Bio-ecological value

Cost as a proxy for value

Replacement 

cost

Monetary estimate of the cost of replacing an ecosystem 

service using the next best available alternative

Lower bound on 

economic value only 

under limited conditions

Habitat 

equivalency 

analysis

Units of habitat (e.g., equivalent acres of habitat) or other 

compensating changes needed to replace ecosystem 

services lost through a natural resource injury

Biophysical value; not 

economic value except 

under some very limited 

conditions

of the good or service being valued should result in an 

increase in the magnitude of expressed values. This 

form of validity has been termed construct validity 

(Fischhoff, 1997; Mitchell and Carson, 1989).

o Are the expressions of value resulting from the 

method stable (i.e., reliable) in the sense that they 

do not change upon further reflection (Fischhoff, 

1997) and are not unduly influenced by irrelevant 

characteristics of the researcher, process facilitator, 

or group?

o To what extent does the information elicited from 

participants in the application of the method (e.g., 

survey respondents or focus group participants) 

provide information that can be used to reliably infer 

something about the values of the targeted group 

within the relevant population? 

These criteria would generally be viewed as necessary 

for validity, although they are not necessarily sufficient to 

guarantee it. Methods can also be evaluated on the extent 

to which the resulting value estimates can be transparently 

communicated in a useful format to those who will use the 

value information. Decision makers and the public should 

be able to understand how the value measures relate to and 

inform the decision that needs to be made.

4.2 An expanded set of methods

This section provides an overview of, and 

introduction to, the wide array of methods considered 

by the committee for possible use in implementing 

the valuation process proposed in chapter 2. Table 

3 provides a listing of these methods, along with an 

overview of the form of output from each method 

and the concept(s) of value that it seeks to measure 

or elicit. Note that, although the concepts of value 

discussed in chapter 2 are conceptually distinct from 

valuation methods, methods generally seek to measure 

specific value concepts, as indicated in Table 3. 

Hence, specific methods are generally associated with 

specific concepts of value. However, methods can be 

complementary, and a given method can sometimes 

be used to provide information that could be useful 

in assessing other concepts of value. For example, 

as discussed in chapter 2, some of the non-economic 

methods in Table 3 can be useful in supporting and 

improving economic valuation.

The following discussion of methods is illustrative 

and introductory rather than comprehensive. The goal 

is to provide the reader with sufficient information 

about the methods to allow a preliminary assessment 

of the role that various methods can play in 
44

implementing the proposed valuation process and to 

direct the interested reader to the relevant scientific 

literature for further information. 

The SAB Web site provides supplemental detailed 

discussions of these methods, including their perceived 

strengths and weaknesses, that were provided by 

individual committee members (http://yosemite.epa.

gov/sab/sabproduct.nsf/WebBOARD/C-VPESS_Web_

Methods_Draft?OpenDocument).34 In addition, federal 

agencies have extensively used surveys to elicit valuerelated information.35 The SAB Web site provides 

a separate, detailed discussion of the use of survey 

methods for ecological valuation. This information 

(http://yosemite.epa.gov/Sab/Sabproduct.nsf/WebFiles/

SurveyMethods/$File/Survey_methods.pdf) is relevant 

to those economic and other methods discussed below 

that rely on surveys. 

4.2.1 Measures of attitudes, preferences, and 

intentions

Social-psychological approaches to assessing the 

value of ecosystems and ecosystem services employ 

a number of methods to identify, characterize, and 

measure the values people hold, express, and advocate 

with respect to changes in ecological states or their 

personal and social consequences. These methods 

elicit value-relevant perceptions and judgments, 

typically expressed as choices, rankings, or ratings 

among presented sets of alternative ecosystems 

protection policies and may include comparisons with 

potentially competing social and economic goals. 

Individuals making these judgments may respond on 

their own behalf or on behalf of others (e.g., society at 

large or specified subgroups). The basis for judgments 

can be changes in individual well-being or in civic, 

ethical, or moral obligations. 

Social-psychological value-assessment approaches 

have relied most strongly on survey methods. For a 

general discussion of the use of surveys in valuation, 

see http://yosemite.epa.gov/Sab/Sabproduct.nsf/

WebFiles/SurveyMethods/$File/Survey_methods.

pdf. Survey questions eliciting information about 

attitudes, preferences, and intentions are most often 

presented in a verbal format, either in face-to-face 

or telephone interviews or in printed questionnaires. 

Assessments of values for ecosystems and ecosystem 

services can be well-conveyed in perceptual surveys 

(e.g., assessments based on photographs, computer 

visualizations, or multimedia representations of 

targeted ecosystem attributes) and conjoint surveys 

(e.g., requiring choices among alternatives that 

systematically combine multiple and potentially 

competing attributes). Quantitative analyses of survey 

responses are usually interpreted as ordinal rankings 

or rough interval-scale measures of differences in 

assessed values for the alternatives offered. Survey 

questions about social and psychological constructs 

may be especially useful when the values at issue are 

difficult to express or conceive in monetary terms, or 

where monetary expressions are likely to be viewed as 

ethically inappropriate. 

Further reading

Adamowicz, W., P. Boxall, M. Wilhams, and J. 

Louviere. 1998. Stated preference approaches 

for measuring passive use values: Choice 

experiments and contingent valuation. American 

Journal of Agricultural Economics 80: 64-67.

Dillman, D.A. 1991. The design and administration 

of mail surveys. Annual Review of Sociology 17: 

225-249.

Dunlap, R.E., K.D. Van Liere, A.G. Mertig, and 

R.E. Jones. 2000. Measuring endorsement of the 

New Ecological Paradigm: A revised NEP scale. 

Journal of Social Issues 56: 425-442. 

Krosnick, J.A. 1999. Survey research. Annual 

Review of Psychology 50: 537-67.

Mace, B.L., P.A. Bell, and R.J. Loomis. 1999. 

Aesthetic, affective, and cognitive effects of 

noise on natural landscape assessment. Society & 

Natural Resources 12: 225-243.

Malm, W., K. Kelly, J. Molenar, and T.C. Daniel. 

1981. Human perception of visual air quality: 

Uniform haze. Atmospheric Environment 15: 

1874-1890. 

Ribe, R.G., E.T. Armstrong, P.H. Gobster. 2002. 

Scenic vistas and the changing policy landscape: 

Visualizing and testing the role of visual 

resources in ecosystem management. Landscape 

Journal 21: 42-66.

Schaeffer, N.C. and S. Presser. 2003. The science 

of asking questions. Annual Review of Sociology

29: 65-88.

Tourangeau, R. 2004. Survey research and 

societal change. Annual Review of Psychology

55: 775-801.

Wilson, T.D., D.J. Lisle, D. Kraft, and C.G. Wetzel, 

1989. Preferences as expectation-driven 

inferences: Effects of affective expectations on 

affective experience. Journal of Personality and 

Social Psychology 56: 4519-530.

Individual narratives and focus group methods 

have also been used in values assessments, but these 

methods are generally more appropriately used as 

formative tools for the design and testing of formal 

quantitative surveys. While surveys are typically 

based on quantitative analyses of responses from large 

representative samples, individual narrative methods

– including mental-model analyses, ethnographic 

analyses, and other relatively unstructured individual 

interviews – generally employ small samples of 

informants and analyze responses qualitatively. For 

example, mental models studies seek to assess how 

informed people are about the consequences of specific 

decisions and their decision-relevant beliefs. Mental 
45

models studies of risk communication explicitly 

compare causal beliefs with formal decision models.36

How people understand relevant causal processes – 

that is, in this case, their mental models of ecosystems 

and the services they provide – can be critical to their 

judgment of the outcomes and effects of environmental 

programs and can influence their preferences among 

policy alternatives. Similarly, focus groups can be 

used to elicit information about values and preferences 

from small groups of relevant members of the public 

engaging in group discussion led by a facilitator. 

Rigorous qualitative analyses of transcripts from 

individual narratives (including mental models studies) 

or focus groups can expose subtle differences in 

individual beliefs and perspectives and the inferential 

bases of participants’ expressed values. However, the 

use of qualitative measures and the uncertainty of 

any generalizations of results from small respondent 

samples limit the utility of these methods for formal 

policy and decision making. 

Given the small number of participants, the goal 

of individual narratives and focus groups is rarely 

to assess the public’s values per se. Rather, these 

methods seek to identify the types and range of value 

perspectives, positions, and concerns of individual 

participants, and to use this information to identify 

the ecosystem effects that might be particularly 

important to the public. The open-ended nature of 

these methods can reveal perspectives and concerns 

that more structured methods might miss. Thus, 

these methods can provide useful input early in a 

valuation process. For example, they are often used 

in the early stages of designing a formal survey to 

elicit quantitative value information from a broader 

representative sample (a “probability sample”) of the 

relevant population. 

Further reading

Bostrom, A., B. Fischhoff, and M.G. Morgan, 

2002. Characterizing mental models of 

hazardous processes: A methodology and an 

application to radon. Journal of Social Issues

48: 85-100.

Brandenburg, A.M., and M.S. Carroll. 1995. Your 

place or mine? The effect of place creation on 

environmental values and landscape meanings. 

Society & Natural Resources 8: 381-398.

Gentner, D., and Whitley, E.W. 1997. Mental 

models of population growth: A preliminary 

investigation. In Environment, ethics, and 

behavior: The psychology of environmental 

valuation and degradation, ed. M. Bazerman, 

D.M. Messick, A.E. Tenbrunsel, and K. WadeBenzoni, 209-233. San Francisco, CA: New 

Lexington Press.

Kempton, W. 1991. Lay perspectives on global 

climate change. Global Environmental Change

1: 183-208.

Merton, R.K., Fiske, M., and Kendall, P.L. 1990. 

The focused interview: A manual of problems 

and procedures. 2nd ed. London: Collier 

MacMillan.

Morgan, M.G., B. Fischhoff, A. Bostrom, C.J. 

Atman. 2002. Risk communication: A mental 

models approach. Cambridge: Cambridge 

University Press.

Satterfield, T., and S. Slovic, eds. 2004. What’s 

nature worth: Narrative expressions of 

environmental values. Salt Lake City: 

University of Utah Press.

Zaksek, M., and J. L. Arvai. 2004. Toward 

improved communication about wildland fire: 

Mental models research to identify information 

needs for natural resource management. Risk 

Analysis 24: 1503-1514.

Recently, researchers have explored the use of 

behavioral observation methods for obtaining 

information about people’s values. These methods elicit 

values information through observations of behavioral 

responses by individuals interacting with either actual or 

computer-simulated environments. Observing how the 

activities of people change as environmental conditions 

change can reveal information about the importance of 

these changes to those people. Researchers can observe 

changes in actual behavior (e.g., visitation rates) or virtual 

behavior (e.g., responses in interactive computer simulation 

games). Behavioral observation methods are consistent 

with other revealed preference methods (see the following 

section), but they are still relatively new and untested, 

particularly in the context of valuing ecosystem services. 

Nonetheless, they show promise for use in this context.

Further reading

Bishop, I. D. and B. Rohrmann. 2003. Subjective 

responses to simulated and real environments: A 

comparison. Landscape and Urban Planning 65: 

261-267.

Gimblett, H.R., T.C. Daniel, S. Cherry, and M. J. 

Meitner. 2001. The simulation and visualization 

of complex human-environment interactions. 

Landscape and Urban Planning 54: 63-79.

Wang, B. and R.E. Manning. 2001. Computer 

simulation modeling for recreation 

management: A study on carriage road 

use in Acadia National Park, Maine, USA. 

Environmental Management 23: 193-203.

Zacharias, J. 2006. Exploratory spatial behaviour 

in real and virtual environments. Landscape and 

Urban Planning 78: 1-13.

4.2.2 Economic methods

Economic valuation methods seek to measure the 

tradeoffs individuals are willing to make for ecological 

improvements or to avoid ecological degradation, 

given the constraints they face. An ecological change 

improving a resource that an individual values will 
46

increase that person’s utility. The marginal value or 

economic benefit of that change is defined to be the 

amount of another good that the individual is willing 

to give up to enjoy that change (willingness-to-pay) 

or the amount of compensation that a person would 

accept in lieu of receiving that change (willingness 

to accept). Although these tradeoffs are typically 

expressed in monetary terms, economic methods that 

express tradeoffs in non-monetary terms (such as 

conjoint analysis or other choice-based methods) are 

increasingly being used. 

Economic methods can estimate values not only 

for goods and services for which there are markets but 

also for non-market goods and services. Economic 

methods can also value both use and non-use (e.g., 

existence) values. Thus, economic valuation captures 

values that extend well beyond commercial or market 

values. However, economic valuation does not capture 

non-anthropocentric values (e.g., biocentric values) and 

values inconsistent with the principle of trrade-offs (such 

as values based on the concept of intrinsic rights). 

There are multiple economic valuation methods that 

can be used to estimate economic values. These include 

methods based on observed behavior (market-based and 

revealed-preference methods) and methods based on 

information elicited from responses to survey questions 

about hypothetical tradeoffs (e.g., stated-preference 

methods). Some of these methods are more applicable to 

some contexts than to others. 

Market-based methods seek to use information 

about market prices (or market demand) to infer values 

related to changes in marketed goods and services. 

For example, when ecological changes lead to a small 

change in timber or commercial fishing harvests, the 

market price of timber or fish can be used as a measure 

of willingness to pay for that marginal change. If the 

change is large, the current market price alone is not 

sufficient to determine value. Rather, the demand 

for timber or fish at various prices must be used to 

determine willingness to pay for the change. In general, 

market-based methods can value only those services 

supplied in well-functioning markets. These methods 

have been used to assess the welfare effects of a wide 

variety of public policies.

Further reading

Barbier, E.B., and I. Strand. 1998. Valuing 

mangrove-fishery linkages. Environmental and 

Resource Economics: 12: 151-166.

Boardman, A.E., D.H. Greenberg, A.R. Vining, 

and D.L. Weimer. 2006. Cost-benefit analysis: 

Concepts and practice. 3rd ed. Upper Saddle 

River, NJ: Prentice-Hall.

Freeman, A.M., III. 2003. The measurement of 

environmental and resource values. 2nd ed. 

Washington, DC: Resources for the Future.

Hufbauer, G., and K.A. Elliott. 1994. Measuring 

the costs of protection in the US. Washington, 

DC: Institute for International Economics.

McConnell, K.E., and N.E. Bockstael. 2005. 

Valuing the environment as a factor of 

production. In Handbook of environmental 

economics, ed. K-G. Maler and J.R. Vincent. 

Amsterdam: North-Holland.

Winston, C. 1993. Economic deregulation: Days 

of reckoning for microeconomists. Journal of 

Economic Literature.

Revealed-preference methods exploit the 

relationship between some forms of individual 

behavior (e.g., visiting a lake or buying a house) and 

associated environmental attributes (e.g., of the lake 

or the house) to estimate value. For example, travel 

cost methods (including applications using random 

utility models) use information about how much people 

implicitly or explicitly pay to visit locations with 

specific environmental attributes including, specific 

levels of ecosystem services, to infer how much they 

value changes in those attributes. Hedonic pricing

uses information about how much people pay for 

houses or other directly-purchased items with specific 

environmental attributes (e.g., visibility, proximity to 

amenities or disamenities) to infer how much they value 

changes in those attributes. It also may use information 

about the wages people would be willing to accept for 

jobs with differing mortality or morbidity risk levels to 

infer how much they value changes in those risks. In 

contrast, averting-behavior methods use observations 

on how much people spend to avoid adverse effects, 

including environmental effects to infer how much they 

value or are willing to pay for the improvements those 

expenditures yield.

Further reading

General

Bockstael, N.B., and K.E. McConnell. 2007. 

Environmental and resource valuation with 

revealed preferences: A theoretical guide to 

empirical models (The economics of non-market 

goods and resources) New York: Springer.

Travel costs

Phaneuf, D.J., and V.K. Smith. 2005. Recreation 

demand models. In Handbook of environmental 

economics, vol. 2, ed. K. Mäler and J. Vincent. 

Amsterdam: North-Holland.

Randall, A. 1994. A difficulty with the travel cost 

method. Land Economics 70: 88-96.

Smith, V.K. and Y. Kaoru. 1990. Signals or noise? 

Explaining the variation in recreational benefit 

estimates. American Journal of Agricultural 

Economics 72: 419-433.

Walsh, R.G., D.M. Johnson, and J.R. McKean. 

1992. Benefit transfer of outdoor recreation 

demand studies, 1968-1988. Water Resources 

Research 28: 707-713.
47

Hedonic pricing

Cropper, M.L, L. Deck, and K.E. McConnell. 

1988. On the choice of functional forms for 

hedonic price functions. Review of Economics 

and Statistics 70: 668-75.

Mahan, B.L., S. Polasky, and R.M. Adams. 2000. 

Valuing urban wetlands: A property price 

approach. Land Economics 76: 100-113.

Palmquist, R.B. 2005. Hedonic models. In 

Handbook of environmental economics, vol. 2, 

ed. K. Mäler and J. Vincent. Amsterdam: NorthHolland.

Smith, V.K., C. Poulos, and H. Kim. 2002. Treating 

open space as an urban amenity. Resource and 

Energy Economics 24: 107-129.

Averting behavior

Dickie, M. 2003. Defensive behavior and damage 

cost methods. In A primer on non-market 

valuation, ed. P.A. Champ, K.J. Boyle, and T.C. 

Brown. Dordrecht: Kluwer Academic Press.

Smith, V.K. 1991. Household production functions 

and environmental benefit estimation. In 

Measuring the demand for environmental 

quality, ed. J.B. Braden and C.D. Kolstad. 

Amsterdam: North-Holland.

In contrast to revealed-preference methods, statedpreference methods infer values or economic benefits from 

responses to survey questions about hypothetical tradeoffs. 

As with social-psychological methods, stated-preference 

methods often use focus groups to improve survey designs. 

In some cases, survey questions directly elicit information 

about willingness to pay or accept, while under some survey 

designs (e.g., conjoint or contingent behavior designs) 

monetary measures of benefits are not expressed directly. 

Rather, quantitative analysis of the tradeoffs implied by 

survey responses is needed to derive economic benefit 

measures. Although the use of stated-preference methods 

for environmental valuation has been controversial, there 

is considerable evidence that the hypothetical responses 

in these surveys provide useful evidence regarding values 

(see related detailed discussion on the use of survey 

methods for ecological valuation on the SAB Web site at 

http://yosemite.epa.gov/Sab/Sabproduct.nsf/WebFiles/

SurveyMethods/$File/Survey_methods.pdf). 

Further reading

Arrow, K., et al. 1993. Report of the NOAA Panel 

on Contingent Valuation, Federal Register 

58:10 (Jan. 15, 1993), 4601-4614.

Banzhaf, S., D. Burtraw, D. Evans, and A. 

Krupnick. 2004. Valuation of natural resource 

improvements in the Adirondacks. Washington, 

DC: Resources for the Future.

Bateman, I.J., and K.G. Willis, eds. 1999. Valuing 

environmental preferences: Theory and practice 

of the contingent valuation method in the US, 

EU, and developing countries. Oxford: Oxford 

University Press.

Carson, R.T. and W.M. Hanemann, 2005, 

Contingent Valuation in Handbook of 

Environmental Economics Vol. II, ed. K. GöranMäler and J. R. Vincent Amsterdam: North 

Holland, pp. 821-936.

Champ, P., K.J. Boyle and T.C. Brown, eds. 2003. 

A primer on non-market valuation. Dordrecht: 

Klumer Academic.

Freeman, A.M., III. 2003. The measurement of 

environmental and resource values, 2nd ed. 

Washington, DC: Resources for the Future.

Haab, T.C. and K.E. McConnell. 2002. Valuing 

environmental and natural resources. 

Cheltenham, UK: Edward Elgar.

Kanninen, B.J., ed. 2007. Valuing environmental 

amenities using stated choice studies. Dordrecht: 

Springer.

Kopp, R.J., W.W. Pommerehne, and N. Schwarz, 

eds. 1997. Determining the value of nonmarketed goods: Economic, psychological, and 

policy relevant aspects of contingent valuation 

methods. Boston: Kluwer Academic Publishers.

Murphy, J.J., P.G. Allen, T.H. Stevens, and 

D. Weatherhead. 2005. A meta-analysis of 

hypothetical bias in stated preference valuation. 

Environmental and Resource Economics, 30: 

313-325.

Smith, V.K. 1997. Pricing what is priceless: 

A status report on non-market valuation of 

environmental resources. In The International 

Yearbook of Environmental and Resource 

Economics, eds. H. Folmer and T. Tietenberg. 

Cheltenham, U.K.: Edward Elgar, pp. 156-204

4.2.3 Civic valuation

Civic valuation seeks to measure the values that people 

place on changes in ecosystems or ecosystem services 

when explicitly considering or acting in their role as 

citizens. These valuation methods often seek to value 

changes that would benefit or harm the community at large. 

They purposefully seek to assess the full value that groups 

attach to any increase in community well-being attributable 

to changes in the relevant ecosystems and services. 

Civic valuation, like economic valuation, can elicit 

information about values either through revealed 

behavior or through stated valuations. One source of 

information based on revealed behavior is votes on 

public referenda and initiatives involving the provision 

of environmental goods and services (e.g., purchases 

of open space). Another source is community decisions 

to accept compensation for permitting environmental 

damage (e.g., by hosting noxious facilities). Where 

revealed values are difficult or impossible to obtain, 

citizen valuation juries or other representative groups can 

be charged with determining the value they would place 

on changes in particular ecological systems or services 

when acting on behalf of, or as a representative of, the 

citizens of the relevant community.
48

Referenda or initiatives can provide information 

about how members of the voting population value 

a particular governmental action involving the 

environment. Analysis of referenda or initiatives can 

reveal whether the majority of the voting population 

feels that a given environmental improvement is 

worth what it will cost the relevant government body, 

given a particular means of financing the associated 

expenditure (and hence, an anticipated cost to the 

individual who is voting). In casting their votes, 

individuals may consider not only what they personally 

would gain or lose but also what the community as a 

whole stands to gain or lose if the proposal is adopted. 

Similarly, analyses of public votes about whether to 

accept an environmental degradation (e.g., through 

hosting a noxious facility) seek to determine if the 

majority of the voting population in that community 

feels that the environmental services that would be 

lost are worth less than the contributions to well-being 

the community would realize (e.g., in the form of tax 

revenues, jobs, or monetary compensation). 

These approaches provide information about the 

policy preferences of the median voter and, under 

certain conditions, provide information about the 

mean valuations of those who participate in the voting 

process. To the extent that voters consider their own 

budget constraints when voting, these valuations reflect 

economic values, i.e., willingness to pay or willingness 

to accept. As with all economic values, the revealed 

economic value reflects both personal benefits and costs, 

as well as any altruistic motivation (public regardedness) 

individual voters have when casting their votes.

Further reading

Banzhaf, S., W. Oates, J.N. Sanchirico, D. 

Simpson, and R. Walsh. 2006. Voting for 

conservation: What is the American electorate 

revealing? Resources 16. Washington, DC: 

Resources for the Future. http://ww.rff.org/rff/

news/features/loader.cfm?url=/commonspot/

security/getfile.cfm&pageid=22017.

Butler, D., and A. Ranney, eds. 1978. Referendums. 

Washington DC: American Enterprise Institute.

Cronin, T.E. 1989. Direct democracy: The politics 

of referendum, initiative and recall. Cambridge: 

Harvard University Press.

Deacon, R., and P. Shapiro. 1975. Private 

preference for collective goods revealed through 

voting on referenda. American Economic 

Review 65: 793.

Kahn, M.E., and J.G. Matsusaka. 1997. Demand 

for environmental goods: Evidence from voting 

patterns on California initiatives. Journal of 

Law and Economics 40: 137-173.

List, J., and J. Shogren. 2002. Calibration of 

willingness-to-accept. Journal of Environmental 

Economics and Management 43: 219-233.

Lupia, A. 1992. Busy voters, agenda control, and 

the power of information. American Political 

Science Review 86: 390-399.

Magleby, D. 1984. Direct legislation: Voting 

on ballot propositions in the United States. 

Baltimore, MD: Johns Hopkins University 

Press.

Murphy, J.J., P.G. Allen, et al. 2003. A metaanalysis of hypothetical bias in stated 

preference valuation. Amherst: Department 

of Resource Economics, University of 

Massachusetts.

Sagoff, M. 2004. Price, principle and the 

environment. Cambridge: Cambridge University 

Press.

Schläpfer, F., A. Roschewitz, and N. Hanley. 2004. 

Validation of stated preferences for public 

goods: A comparison of contingent valuation 

survey response and voting behavior. Ecological 

Economics 51: 1-16.

Shabman, L., and K. Stephenson. 1996. Searching 

for the correct benefit estimate: Empirical 

evidence for an alternative perspective. Land 

Economics 72: 

433-49.

Vossler, C.A., J. Kerkvliet, S. Polasky, and O. 

Gainutdinova. 2003. Externally validating 

contingent valuation: An open-space survey 

and referendum in Corvallis, Oregon. Journal 

of Economic Behavior and Organization 51: 

261-277.

In contrast to initiatives and referenda, citizen valuation 

juries measure stated rather than revealed value. They also 

incorporate elements of the deliberative valuation process 

(see chapter 5). The jury is given extensive information 

and, after a lengthy discussion, usually asked to agree on a 

common value or make a group decision. To date, citizen 

juries have typically been asked to develop a ranking of 

alternative options for achieving a given goal. Although 

citizen juries have been used in other contexts, experience 

using citizen juries for ecological valuation is very limited. 

Nonetheless, in principle, a jury could be asked to generate 

a value for how much the public would, or should, be 

willing to pay for a possible environmental improvement, 

or, conversely, willing to accept for an environmental 

degradation. In contrast to estimates of willingness to pay 

derived from economic valuation methods, the estimates 

from citizen juries would not reflect the budget constraints 

of the individual participants and would reflect communitybased values rather than economic values. To the extent 

that a citizen jury engages in group deliberation, resulting 

value estimates also would reflect constructed values. 

Further reading

Aldred, J., and M. Jacobs. 2000. Citizens and 

wetlands: Evaluating the Ely citizens’ jury. 

Ecological Economics 34: 217-232.
49

Alvarez-Farizo, B., and N. Hanley. 2006. 

Improving the process of valuing non-market 

benefits: Combining citizens’ juries with choice 

modelling. Land Economics 82: 465-478.

Blamey, R.K., et al. 2000. Citizens’ juries and 

environmental value assessment. Canberra: 

Research School of Social Sciences, Australian 

National University.

Brown, T.C., et al. 1995. The values jury to aid 

natural resource decisions. Land Economics 71: 

250-260.

Gregory, R., and K. Wellman. 2001. Bringing 

stakeholder values into environmental policy 

choices: A community-based estuary case study. 

Ecological Economics 39: 37-52.

Kenyon, W., and N. Hanley. 2001. Economic and 

participatory approaches to environmental 

evaluation. Glasgow, U.K.: Economics 

Department, University of Glasgow.

Kenyon, W., and C. Nevin. 2001. The use of 

economic and participatory approaches to 

assess forest development: A case study in the 

Ettrick Valley. Forest Policy and Economics 3: 

69-80.

Macmillan, D.C., et al. 2002. Valuing the nonmarket benefits of wild goose conservation: 

A comparison of interview and group-based 

approaches. Ecological Economics 43: 49-59.

McDaniels, T.L., et al. 2003. Decision structuring 

to alleviate embedding in environmental 

valuation. Ecological Economics 46: 33-46.

O’Neill, J., and C.L. Spash. 2000. Appendix: 

Policy research brief: conceptions of value in 

environmental decision-making. Environmental 

Values 9: 521-536.

4.2.4 Decision science methods

Decision science valuation methods derive 

information about people’s values through a 

deliberative process that helps individuals understand 

and assess tradeoffs among multiple attributes. The 

ultimate goal is to have an individual or group assign 

scores to alternatives (e.g., different projects) that 

can then be used to choose among those alternatives, 

recognizing that those alternatives will differ along 

a number of relevant dimensions or attributes. 

Generally, one alternative will score higher along 

some dimensions but not others, suggesting that 

tradeoffs must be made when choosing among 

alternatives. 

Decision science valuation methods are typically 

embedded in a decision-aiding process. As part of the 

process, an expert facilitator helps the individual or 

group decompose the choice problem by identifying 

and operationalizing objectives as well as relevant 

attributes. For example, people may feel that the value 

of a project to protect an estuary depends on attributes 

such as the estuary’s ability to provide nutrient 

exchange and nursery habitat for anadromous fish, the 

opportunities it provides for recreation, and the cost 

of the project. The facilitator leads the individual or 

group through a process by which they assign weights 

to each of the attributes. A variety of approaches to 

assigning weights have been used, including assigning 

importance points, eliciting ratio weights, determining 

swing weights, and pricing out attributes. These 

weights reflect the tradeoffs that the individual or group 

is willing to make across attributes, and hence reveal 

information about values. 

Once the attribute weights are determined, an 

aggregating function (or utility function) is used to 

combine the weights and attribute levels into a score (or 

measure of multi-attribute utility) for each alternative. 

Ranking alternative projects or options based on these 

scores can provide information about which option (and 

hence which combination of attributes) is viewed as 

more valuable. 

Further reading

Arvai, J.L., and R. Gregory. 2003. Testing 

alternative decision approaches for identifying 

cleanup priorities at contaminated sites. 

Environmental Science & Technology 37:1469-

1476.

Clemen, R.T. 1996. Making hard decisions: An 

introduction to decision analysis. Boston: PWSKent Publishing.

Gregory, R., J.L. Arvai, and T. McDaniels. 2001. 

Value-focused thinking for environmental risk 

consultations. Research in Social Problems and 

Public Policy 9: 249-275.

Gregory, R., S. Lichtenstein, and P. Slovic, P. 

1993. Valuing environmental resources: A 

constructive approach. Journal of Risk and 

Uncertainty 7: 

177-197.

Hammond, J.S., R.L. Keeney, and H. Raiffa. 1998. 

Even swaps: A rational method for making 

trade-offs. Harvard Business Review 76: 137-

138, 143-148, 150.

Hammond, J., R.L. Keeney, and H. Raiffa. 1999. 

Smart choices: A practical guide to making 

better decisions. Cambridge: Harvard Business 

School Press.

Keeney, R.L. 1992. Value-focused thinking. A 

path to creative decision making. Cambridge: 

Harvard University Press.

Keeney, R.L., and H. Raiffa. 1993. Decisions with 

multiple objectives: Preferences and value 

tradeoffs. Cambridge: Cambridge University 

Press. 

Payne, J.W., J.R. Bettman, and E.J. Johnson. 1992. 

Behavioral decision research: A constructive 

processing perspective. Annual Review of 

Psychology 43: 87-132.

Slovic, P. 1995. The construction of preference. 

American Psychologist 50: 364-371.
50

4.2.5 Ecosystem benefit indicators

Ecosystem benefit indicators offer quantitative 

metrics that are generally correlated with ecological 

contributions to human well-being and hence can 

serve as indicators for these contributions in a specific 

setting. They use geo-spatial data to provide information 

related to the demand for, supply (or scarcity) of, and 

complements to particular ecosystem services across 

a given landscape, based on social and biophysical 

features that influence – positively or negatively – 

the contributions of ecosystem services to human 

well-being. Examples of these indicators include the 

percentage of a watershed in a particular land use or of 

a particular land type, the number of users of a service 

(e.g., water or recreation) within a given area, and the 

distance to the nearest vulnerable human community. 

Ecological benefit indicators can serve as important 

quantitative inputs to valuation methods as diverse 

as citizen juries and economic valuation methods. 

Ecosystem benefit indicators provide a way to illustrate 

factors influencing ecological contributions to human 

welfare in a specific setting. The method can be applied 

to any ecosystem service where the spatial delivery of 

services is related to the social landscape in which the 

service is enjoyed. However, although the resulting 

indicators can be correlated with other value measures, 

such as economic values, they do not themselves provide 

measures of value.

Further reading

Boyd, J. 2004. What’s nature worth? Using 

indicators to open the black box of ecological 

valuation. Resources.

Boyd, J., D. King, and L. Wainger. 2001. 

Compensation for lost ecosystem services: 

The need for benefit-based transfer ratios and 

restoration criteria. Stanford Environmental 

Law Journal 20.

Boyd, J., and L. Wainger 2002. Landscape 

indicators of ecosystem service benefits. 

American Journal of Agricultural Economics 

84.

Wainger, L., D. King, J. Salzman, and J. Boyd. 

2001. Wetland value indicators for scoring 

mitigation trades. Stanford Environmental Law 

Journal 20.

4.2.6 Biophysical ranking methods

In some contexts, policy makers or analysts 

are interested in values based on quantification of 

biophysical indicators. Possible indicators include 

measures of biodiversity, biomass production, 

carbon sequestration, or energy and materials use.37

Quantification of ecological changes in biophysical 

terms allows these changes to be ranked based on 

individual or aggregate indicators for use in evaluating 

policy options based on biophysical criteria previously 

determined to be relevant to human/social well-being. 

Use of a biophysical ranking does not explicitly 

incorporate human preferences. Rather, it reflects either a 

non-anthropocentric theory of value (based, for example, 

on energy flows) or a presumption that the indicators 

provide a proxy for human value or social preference. 

This latter presumption is predicated on the belief that 

the healthy functioning and sustainability of ecosystems 

is fundamentally important to the well-being of human 

societies and all living things, and that the contributions 

to human well-being of any change in ecosystems can be 

assessed in terms of the calculated effects on ecosystems. 

Opinion is mixed – among both committee members and 

the broader scholarly community – on whether it is an 

asset or a drawback that these ranking methods are not 

tied directly to human preferences. 

The committee discussed two types of biophysical 

rankings. The first is a ranking method based on 

conservation value. The conservation value method

develops a spatially-differentiated index of conservation 

value across a landscape based on an assessment of 

rarity, persistence, threat, and other landscape attributes, 

reflecting the contribution of these attributes to sustained 

ecosystem diversity and integrity. These values can be 

used to prioritize land for acquisition, conservation, or 

other purposes, given relevant biophysical goals. Based 

on geographic information system (GIS) technology, 

the method can combine information about a variety of 

ecosystem characteristics and services across a given 

landscape and overlay ecological information with 

other spatial data. Conservation values have been used 

in various contexts by federal agencies (e.g., the U.S. 

Forest Service, Fish and Wildlife Service, National 

Park Service, and Bureau of Land Management), 

non-governmental organizations (e.g., The Nature 

Conservancy and NatureServe), and by regional and 

local planning agencies.

Further reading

Brown, N., L. Master, D. Faber-Langendoen, P. 

Comer, K. Maybury, M. Robles, J. Nichols, 

and T.B. Wigley. 2004. Managing elements of 

biodiversity in sustainable forestry programs: 

Status and utility of NatureServe’s information 

resources to forest managers. National Council 

for Air and Stream Improvement Technical 

Bulletin Number 0885.

Grossman, D.H., and P.J. Comer. 2004. Setting 

priorities for biodiversity conservation in 

Puerto Rico. NatureServe Technical Report.

Riordan, R. and K. Barker. 2003. Cultivating 

biodiversity in Napa. Geospatial Solutions 

November 2003.

Stoms, D.M., P.J. Comer, P.J. Crist and D.H. 

Grossman. 2005. Choosing surrogates for 

biodiversity conservation in complex planning 

environments. Journal of Conservation 

Planning 1.
51

The second group of biophysical methods that the 

committee discussed quantify the flows of energy and 

materials through complex ecological systems, economic 

systems, or both. Ecologists have used these methods 

to identify the resources or resource-equivalents needed 

to produce a product or service, using a systems or 

life-cycle (“cradle to grave”) approach. For example, 

embodied energy analysis measures the total energy, 

direct and indirect, required to produce a good or service. 

Similarly, ecological footprint analysis measures the 

area of an ecosystem (e.g., the amount of land and/or 

water) required to support a certain level and type of 

consumption by an individual or population.38

In addition to using these methods to measure required 

inputs, some ecologists have advocated using the cost 

estimates for embodied energy as a measure of value, 

based on an energy (or other biophysical input) theory of 

value. Although conceptually distinct, they have found 

that these estimates can be of similar magnitude to value 

estimates based on economic valuation methods. 

Further reading

Embodied energy

Ayres, R.U., 1978. Application of physical 

principles to economics. In Resources, 

environment, and economics: Applications of 

the materials/energy balance principle, ed. R.U. 

Ayres, 37-71. New York: Wiley.

Boulding, K.E. 1966. The economics of the 

coming spaceship Earth. In Environmental 

quality in a growing economy, ed. H. Jarrett, 

3-14. Baltimore, MD: Resources for the Future/

Johns Hopkins University Press.

Cleveland, C.J. 1987. Biophysical economics: 

Historical perspective and current research 

trends. Ecological Modelling 38:47-74.

Cleveland, C.J., R. Costanza, C.A.S. Hall, and 

R. Kaufmann. 1984. Energy and the U.S. 

economy: A biophysical perspective. Science 

225: 890-897. 

Costanza, R. 1980. Embodied energy and 

economic valuation. Science 210: 1219-1224.

Costanza, R. 2004. Value theory and energy. In 

Encyclopedia of energy, vol 6, ed. C. Cleveland. 

337-346. Amsterdam: Elsevier. 

Costanza, R., S.C. Farber, and J. Maxwell. 1989. 

The valuation and management of wetland 

ecosystems. Ecological Economics 1: 335-361. 

Hall, C.A.S., C.J. Cleveland, and K. Kaufmann. 

1992. Energy and resource quality: The ecology 

of the economic process. New York: Wiley. 

Hannon, B., R. Costanza, and R.A. Herendeen. 

1986. Measures of energy cost and value in 

ecosystems. The Journal of Environmental 

Economics and Management 13: 391-401.

Kaufmann, R.K. 1992. A biophysical analysis of 

the energy/real GDP ratio: Implications for 

substitution and technical change. Ecological 

Economics 6: 35-56.

Ruth, M. 1995. Information, order and knowledge 

in economic and ecological systems: 

Implications from material and energy use. 

Ecological Economics 13: 99-114.

Ecological footprint analysis 

Costanza, R., ed. 2000. Forum: The ecological 

footprint. Ecological Economics 32: 341-394.

Global Footprint Network. 2008. [cited 2008]. 

Available from http://www.footprintnetwork.

org/en/index.php/GFN/

Herendeen, R. 2000. Ecological footprint is a 

vivid indicator of indirect effects. Ecological 

Economics 32: 357-358

Rees, W.E. 2000. Eco-footprint analysis: Merits 

and brickbats. Ecological Economics 32: 371-

374

Simmons, C., K. Lewis, and J. Moore. 2000. Two 

feet – two approaches: A component-based 

model of ecological footprinting. Ecological 

Economics 32: 375-380

Wackernagel, M., L. Onisto, P. Bello, A. C. 

Linares, I. S. L. Falfan, J. M. Garcia, A. I. 

S. Guerrero, and M. G. S. Guerrero. 1999. 

National natural capital accounting with 

the ecological footprint concept. Ecological 

Economics 29:375-390.

Wackernagel, M., N. B. Schultz, D. Deumling, 

A. C. Linares, M. Jenkins, V. Kapos, C. 

Monfreda, J. Loh, N. Myers, R. B. Norgaard, 

and J. Randers. 2002. Tracking the ecological 

overshoot of the human economy. Proceedings 

of the National Academy of Sciences, USA 

99:9266-9271.

4.2.7 Methods using cost as a proxy for value

A fundamental principle in economics is the 

distinction between benefits and costs. In the context 

of ecosystem services, economic benefits reflect what 

is gained by increasing the amount of a given service 

relative to some baseline, while costs reflect what must 

be given up in order to achieve that increase. Costs can 

provide information about benefits or value only under 

specific and limited conditions. Nonetheless, several 

methods based on costs have been used in the valuation 

of ecosystem services.

One such method is replacement cost. Under this 

method, the value of a given ecosystem service is viewed 

as the cost of replacing that service by some alternative 

means. For example, some studies have valued clean 

drinking water provided by watershed protection by 

using the cost savings from not having to build a water 

filtration plant to provide the clean water (NRC, 2000 

and 2004; Sagoff 2005). This type of cost savings 

can offer a lower-bound estimate of the value of an 

ecosystem service, but only under limited conditions 

(Bockstael et al., 2000). First, there must be multiple 

ways to produce an equivalent amount and quality of 

the ecosystem service. In the above example, the same 
52

quantity and quality of clean water must be provided by 

both the watershed protection and the filtration plant. 

Second, the value of the ecosystem service must be 

greater than or equal to the cost of producing the service 

via this alternative means, so that society would be better 

off paying for replacement rather than choosing to forego 

the ecosystem service. In the example, the value of the 

clean water provided must exceed the cost of providing 

it via the filtration plant. When these two conditions are 

met, it is valid to use the cost of providing the equivalent 

services via the alternative as a lower-bound estimate of 

the economic value of the ecosystem service. 

Further reading

Bartik, T.J. 1988. Evaluating the benefits of 

non-marginal reductions in pollution using 

information on defensive expenditures.” Journal 

of Environmental Economics and Management

15: 111-22.

Bockstael, N.E., A.M. Freeman, et al. 2000. 

On measuring economic values for nature. 

Environmental Science and Technology 34: 

1384-1389.

Chichilnisky, G., and G. Heal. 1998. Economic 

returns from the biosphere. Nature 391: 629-

630.

National Research Council. 2000. Watershed 

management for potable water supply: 

Assessing the New York City strategy.

Washington, DC: National Academies Press.

National Research Council. 2004. Valuing 

ecosystem services: Toward better 

environmental decision-making. Washington, 

DC: National Academies Press.

Sagoff, M. 2005. The Catskills parable. PERC 

Report. Bozeman, MT: Political Economy 

Research Center. 

Shabman, L.A., and S.S. Batie. 1978. The 

economic value of coastal wetlands: A critique. 

Coastal Zone Management Journal 4: 231-237.

Another cost-related concept is habitat 

equivalency analysis (HEA), which has been used 

in Natural Resource Damage Assessments under the 

Comprehensive Environmental Response, Compensation 

and Liability Act and the Oil Pollution Act. HEA 

seeks to determine the restoration projects that would 

provide ecosystem or other related services (including 

capital investments such as boat docks) sufficient to 

compensate for a loss from a natural-resource injury 

(e.g., a hazardous waste release or spill). In principle, to 

determine whether a set of projects provides sufficient 

compensation for a loss, HEA should determine the 

tradeoffs required to make the public whole using utility 

equivalents of the associated losses and gains – i.e., 

it should use a value-to-value approach (see Roach 

and Wade, 2006; Jones and Pease, 1997). However, 

in practice HEA is often based on a service-to-service 

approach specified in biophysical equivalents (e.g., 

acres) rather than utility equivalents (value). Restoring 

habitat far from where people live and recreate, however, 

may not create value equivalent to nearby lost habitat, 

even if the replacement habitat is of the same size. 

Although HEA can provide dollar estimates of the 

cost of providing replacement services or projects, these 

estimates do not necessarily satisfy the two conditions 

noted above that are necessary for replacement cost to 

provide a lower bound on value. For example, the value of 

the ecosystem or other services provided by the restoration 

projects may not exceed the cost of providing those 

services. Even if it does, several other assumptions are 

needed to ensure that HEA will provide an actual estimate 

of the economic value of the lost ecosystem services and 

these assumptions will often not be met in practice. These 

include fixed proportions between services and values, as 

well as unit values that are constant over time and space 

(Dunford et al., 2004).

Because costs and benefits are two distinctly different 

concepts, the committee urges caution in the adoption of 

any methods using costs as a proxy for value. The above 

conditions for valid use must be satisfied. Analyses of 

costs should not be interpreted as measures of benefits 

unless these conditions are met. Nonetheless, when 

appropriately applied, methods such as replacement cost 

and HEA may be useful to EPA in policy contexts where 

there are multiple ways of providing an ecosystem service. 

Further reading

Dunford, R.W., T.C. Ginn and W.H. Desvousges. 

2004. The use of habitat equivalency analysis in 

natural resource damage assessment. Ecological 

Economics 48: 49-70.

King, D.M. 1997. Comparing ecosystem services 

and values: With illustrations for performing 

habitat equivalency analysis. Service Paper 

Number 1. Washington, DC: National Oceanic 

and Atmospheric Administration.

U.S. National Oceanic and Atmospheric 

Administration. 1995. Habitat equivalency 

analysis: An overview. Policy and Technical 

Paper Series No. 95-1 (revised 2000). 

Washington, DC: National Oceanic and 

Atmospheric Administration. 

U.S. National Oceanic and Atmospheric 

Administration. 1999. Discounting and the 

treatment of uncertainty in natural resource 

damage assessment. Technical Paper 99-

1. Washington, DC: National Oceanic and 

Atmospheric Administration, Damage 

Assessment and Restoration Program. 

U.S. National Oceanic and Atmospheric 

Administration. 2001. Damage assessment and 

restoration plan and environmental assessment 

for the Point Comfort/Lavaca Bay NPL site 

recreational fishing service losses. Washington, 

DC: National Oceanic and Atmospheric 

Administration.
53

U.S. National Oceanic and Atmospheric 

Administration. Coastal Service Center Web site. 

Habitat Equivalency Analysis. http://www.darrp.

noaa.gov/library/pdf/heaoverv.pdf

The price of tradable emissions permits under 

cap-and-trade systems will almost never meet the 

requirements for using cost as a proxy for value. The 

price of an emission permit in a well-functioning 

market will reflect the incremental cost of pollution 

abatement. This price does not reflect the value of 

pollution reduction unless one of two conditions is met: 

a) the number of permits is set optimally, so that the 

incremental cost of pollution equals the incremental 

benefit of pollution reduction; or b) there are significant 

purchases of permits for purposes of retiring rather than 

using the permit, which indicates the willingness-to-pay 

for pollution reduction by the purchaser. Absent these 

exceptions, the price of tradable emissions permits 

should not be used as a proxy for value.

4.3 Transferring value information

This section examines the transfer of value 

information from one policy context to another. For 

example, values assessed for a change in ecosystem 

services in one setting (reflecting a combination of 

biophysical and socio-economic conditions) might 

be used to estimate values in a different setting, as 

illustrated by the CAFO example described in section 

2.2.3. Value transfers, especially in the form of benefits 

transfer, have been important to EPA valuation efforts, 

but there are a number of concerns and conditions that 

have important implications for the validity of such 

transfers and that have typically not been consistently 

or adequately addressed. The following discussion 

identifies and addresses concepts and methods that are 

important for achieving valid transfer of any measures 

or data about ecological values, with specific attention 

to the transfer of economic benefits. Parallel conceptual 

and methodological issues apply to all values transfers, 

and very similar issues are involved in the transfer of 

ecological data and information between different policy 

contexts (see the discussion in chapter 3.5.1). 

4.3.1 Transfer of information about economic 

benefits

Economists often use information about economic 

benefits derived from a previous valuation study to 

assign values to changes in another context. This 

process or method is known as benefits transfer. As an 

example, suppose that a hedonic property value study 

used data from the sales of residential homes in Chicago 

(the study site) to estimate the incremental change in 

housing prices associated with variations in the air 

quality conditions near these homes. Given a variety of 

theoretical and statistical assumptions, measures adapted 

from the estimates of these price equations can be used 

to estimate the marginal value of small improvements 

in air quality in another city, such as New York or Los 

Angeles (the policy site). The adjustments necessary 

to use benefit information from a previous study in a 

new context depend on a number of factors, including 

the needs of proposed policy application, the available 

information about the policy site, and the comparability 

of preferences and supply conditions at the study and 

policy sites.

In light of the time and money needed to generate 

original value estimates, EPA relies heavily on benefits 

transfer. In fact, benefits transfer is the primary method 

EPA uses to develop the measures of economic trade-offs 

used in its policy evaluations. Most regulatory impact 

assessments and policy evaluations rely on adaptation 

of information from the existing literature. Recent 

examples of policy evaluations that used benefits transfer 

methods include EPA’s Economic and Benefits Analysis 

for the Final Section 316(b) Phase III Existing Facilities 

Rule, June 1, 2006 (EPA, 2006b), EPA’s Final Report 

to Congress on Benefits and Costs of the Clean Air Act, 

1990 to 2010. (EPA, 1999), and the economic benefitcost analysis of the CAFO regulations. 

EPA’s heavy reliance on benefits transfer raises 

a significant issue regarding its validity: under what 

conditions can the findings derived from existing 

studies be used to estimate values in new contexts? 

Inappropriate benefits transfer often is a weak link 

in valuation studies. A number of environmental 

economists and other policy analysts have devoted 

considerable attention to benefits transfer (e.g., Wilson 

and Hoehn 2006). 

The evaluations of benefits transfer in the literature 

have been mixed. For example, Brouwer (2000) 

concludes that “no study has yet been able to show 

under which conditions environmental value transfer is 

valid” (p. 140). Similarly, Muthke and Holm-Mueller 

(2004) urge analysts to “forego the international benefit 

transfer” and remark that “national benefit transfer 

seems to be possible if margins of error around 50% are 

deemed to be acceptable” (p. 334). On the other hand, 

Shrestha and Loomis (2003) conclude that, “Overall, the 

results suggest that national BTF can be a potentially 

useful benefit transfer function for recreation benefit 

estimation at a new policy site” (pp. 94-95). 

Because benefits transfer constitutes a wide collection 

of methods that arise from the specific needs of each 

policy application, broad conclusions regarding validity 

are not meaningful. Rather, assessment of the validity 

of the approach requires case-by-case evaluation of the 

assumptions used in the specific application of interest 

and must consider the similarities and dissimilarities 

between the study site and the policy site(s). For this 

reason, overall the committee believes that general 

conclusions regarding the validity of the application 

of these methods are not possible. However, some 
54

applications of benefits transfer by EPA have been valid, 

while others have not.

4.3.2 Transfer methods 

As noted, benefits transfer refers to a collection of 

methods rather than a single approach. Values derived 

from one or more study sites can be transferred to a 

policy site in three ways. The first is the transfer of a 

unit value. A unit-value transfer usually interprets an 

estimate of the tradeoff people make for a change in 

environmental services as locally constant for each unit 

of change in the environmental service. For the policy 

site, the relevant and available values for these factors 

are used to estimate an adjusted measure for the unit 

value based on the specific conditions in the policy site 

(see Brouwer and Bateman, 2005 for an example in the 

health context). As noted above, the required adjustments 

will depend on a number of factors. 

A second approach is the function transfer approach, 

which replaces the unit value with a summary function 

describing the results of a single study or a set of 

studies. For example, a primary analysis of the value 

of air-quality improvements might be based on a 

contingent valuation survey of individuals’ willingness 

to pay to avoid specific episodes of ill health, such 

as a minor symptom-day (e.g., a day with mildly red 

watering itchy eyes) or one day of persistent nausea 

and headache with occasional vomiting (e.g., Ready 

et al., 2004). A value function in this context relates 

willingness to pay to respondent characteristics and 

other factors that are likely to influence it, such as 

income, health status, demographic attributes, and the 

availability of health insurance. This value function 

is then used to estimate willingness-to-pay for 

populations with different characteristics. Alternatively, 

the original study might estimate a demand function or 

discrete choice model based on an underlying random 

utility model describing revealed preference choices. 

The demand function or discrete choice model is 

transferred and then used to estimate economic benefits 

at the policy site. In this case, the function being 

transferred is an estimated behavioral model rather than 

a value function. 

Meta-analyses, which statistically combine results 

from numerous studies, can also involve a type of 

function transfer. Meta-analyses can be undertaken 

when there is accumulated evidence on measures 

of economic tradeoffs for a common set of changes 

in resources or amenities, provided that the benefit 

concept that is measured and the resource change that 

is valued are consistent across the studies that are 

combined in the analysis (Smith and Pattanayak, 2002). 

One area with a large number of applications is water 

quality relevant to recreation (e.g., Johnston et al., 

2003; Smith and Kaoru, 1990a, 1990b). EPA recently 

used this approach in its assessment for the Phase III 

component of the 316(b) rules.

Some meta-analyses combine unit values to produce 

a weighted average unit value. While this might be 

appropriate in some valuation contexts (EPA Science 

Advisory Board, 2008a), in the context of ecological 

valuation it can be problematic because it ignores the 

site-specific variation in the value of ecosystem that stems 

from heterogeneity in both ecosystem and population 

characteristics. Alternatively, meta-analyses can combine 

studies to estimate a meta-regression function, which can 

be used to identify both site and population characteristics 

as well as methodological characteristics that influence 

benefit estimates. Such a function has the potential to be 

used for benefits transfer and allows an adjustment for 

characteristics of the policy site, if based on a structural 

approach that ensures that basic consistency properties 

are satisfied in order for the results to yield reliable benefit 

estimates (Bergstrom and Taylor, 2006). These approaches 

to benefit transfer have not yet been widely used. They 

need to be evaluated before it would be possible to describe 

a set of practices for applications, for example, in national 

rule making (see further discussion in section 6.1).

A third approach to benefits transfer is preference 

calibration. It uses information from the study site 

to identify the parameters that describe underlying 

preferences, with the objective of then using the resulting 

preference relationship to estimate benefits at the policy 

site (see Smith et al., 2002). With calibration, not all 

relevant parameters (in this case relating to preferences) 

are estimated directly from the data. Rather, some are 

calculated or inferred from available estimates of other 

parameters and assumed or observed relationships and 

constraints. When the parameters can be calibrated or 

estimated from the existing literature, the transfer uses 

the calibrated preference function, together with the 

conditions at the policy site, to measure the tradeoff for 

the change associated with the policy application. 

4.3.3 Challenges regarding benefits transfer

Several challenges arise when using benefits transfer. 

The first stems from possible differences between the 

study and policy sites. Regardless of the type of transfer 

method used, economic benefits or economic value 

functions derived from a particular ecosystem study site 

will not necessarily be relevant for a different policy site. 

How people value the preservation or alteration of an 

ecosystem depends on two dimensions: their preferences 

and the nature of the biophysical system. Differences 

in both biophysical characteristics and human values 

and preferences dictate that great care must be taken in 

deciding whether the valuation of benefits in one context 

can be validly used in another context. 

Similarities or differences in preferences are likely 

to depend on how close the populations in the two cases 

are along social and economic dimensions that influence 

marginal willingness to pay. For example, income levels 

or age profiles are sometimes relevant, as in many cases 

of valuing recreational opportunities. The particular 
55

cultural characteristics of the community also may be 

relevant. For example, in locations where salmon are 

seen as iconic species reflecting the entire ecosystem 

(e.g., Seattle), people are likely to value more highly 

both salmon and water quality important for preserving 

the salmon. 

When only information on willingness to pay per 

unit of improvement is available, the analyst must be 

sensitive to the types of differences that would render a 

transfer inappropriate. If all the differences between the 

study site and the policy site are such that one is likely 

to have a higher value per unit of improvement than the 

other, the value at the study site can provide either a 

floor or ceiling for the value at the policy site. When the 

information from the study site is in functional terms 

(e.g., willingness to pay as a function of income levels 

or age), social-economic differences between the study 

site and the policy site can be accommodated if these 

specifications are valid. 

Although it may be possible to adjust for differences 

in social-economic characteristics of the populations, 

the capacity to adjust for biophysical differences 

is typically more limited. For example, even if the 

affected populations have identical characteristics 

(or adjustments can be made for their differences), 

the value of improving the water quality of one 

small lake in Minnesota is likely to be quite different 

from improving water quality in a small lake in 

Texas, because the effects on the overall provision of 

ecosystem services are likely to be quite different and 

not captured by a single relationship.

The challenge of transferring benefit estimates 

is exacerbated by the fact that often few economic 

benefit studies are available for use. One consequence 

is that analysts sometimes rely on benefits estimates 

that are too old to be reliable for new applications. For 

example, the regulatory impact assessment conducted 

for the concentrated animal feeding operations 

(CAFO) rule based its willingness-to-pay estimates 

for improved water quality on indices taken from a 

contingent valuation survey conducted by Carson 

and Mitchell in November 1983, 20 years before 

EPA’s final CAFO rule was published (see Carson and 

Mitchell, 1993). In addition, due to lack of suitable 

previous studies, analysts sometimes inappropriately 

use values or functions derived from studies designed 

for purposes other than those relevant for the policy 

site. For example, the Carson and Mitchell study used 

in the CAFO rule was not intended to apply to specific 

rivers or lakes. Moreover, the water quality index used 

by Carson and Mitchell was highly simplified and 

not intended to reflect changes in ecosystem services 

beyond those related to fishing, boating, and swimming. 

An additional challenge stems from the difficulty of 

finding the most appropriate unit values to carry over 

from the study site to the policy site. In the example 

below, illustrating willingness to pay for an improved 

fishing catch rate, several different metrics of value 

are possible, and the different metrics will have very 

different implications for the valuation at the policy site. 

The choice of unit values also has to be appropriate to 

the scale and context. For example, willingness to pay 

for increased wilderness areas in a study site may have 

been expressed in terms of dollars per absolute increase 

in area (e.g., $100 per taxpayer annually for a 100-acre 

increase in area, or $1 per acre). This unit value may be 

reasonable for a small, heavily populated municipality, 

but far too high for a municipality with substantially 

more existing wilderness area.

4.3.4 Improving transfers of value information 

The discussion above points to the need for additional 

research to develop and improve methods and data 

for use in value transfers. While the discussion in 

section 4.3.3. focuses on the specific case of benefits 

transfer, similar challenges arise with other transfers 

of information about values. A number of strategies or 

processes can help improve these transfers. 

One strategy that can help address the challenges 

of determining whether and how to conduct a value 

transfer is the use of a screening process. This 

procedural approach assumes that a deliberate effort 

to examine the similarities and differences between 

study sites and the policy site, by both EPA analysts 

and those overseeing their work, will help flag 

problematic transfers and clarify the assumptions and 

limitations of the study-site results. Several procedures 

can be considered. One is to contact experts familiar 

enough with both the previous and current contexts 

to determine whether to proceed with the proposed 

transfer. These experts can consider input from a 

variety of sources, including the public, and then apply 

the criteria that they regard as relevant, even if the set 

of criteria is not explicit. Experts knowledgeable in 

both the study case and the policy case can suggest 

the most appropriate functional forms and unit values 

(e.g., Desvousges, Johnson, and Banzhaf, 1998). 

Experts may also be able to suggest other existing 

valuations that would be better candidates for transfer 

of value information.

Another procedure is to make a detailed examination 

of the appropriateness of the study case a regular part 

of EPA review of analyses using value transfers. Such 

oversight of the use of case studies would require 

analysts to clarify the assumptions, purposes, and units 

of the study-site analysis so that EPA reviewers can 

judge the appropriateness of the transfer. Analysts must 

also be fully transparent regarding the origin and context, 

including the date, of the original valuation.

More thorough cataloguing of existing valuation 

studies, with careful descriptions of the characteristics 
56

Table 4: Table of alternative unit value transfers

Assumption Unit Value Interpretation of Policy Aggregate Value

Constant unit value 

for a 1% improvement

$0.50 per 1% 

improvement

5% improvement per 

trip

$0.50 x 5 x 3 x 2000 = 

$15,000

Constant unit value 

for an extra fish 

caught per hour of 

effort

$25 per additional fish 

per hour

Added fish caught $25 x .05 x 1 x 3 x 2000 

= $7,500

Constant value for an 

improved trip

$5 per trip Improved fishing trips $5 x 3 x 2000 = $30,000

Suppose estimates from the literature imply that 

the average value of the willingness to pay for a 10% 

improvement in the catch rate (i.e., fish caught per unit 

of effort) for a sport fishing trip is $5 per trip. This 

estimate could be from a study describing specific types 

of fishing trips by a sample of individuals or it could be 

an average of several studies. 

One approach for developing a unit value transfer 

would divide $5 by 10% to generate a unit value 

of $0.50 for each 1% improvement. This strategy 

implicitly assumes the benefit measure is not influenced 

by the level of quality – i.e., to be constant for each 

proportionate improvement. 

Another approach would take the same information 

on average tradeoffs and calculate a unit value using 

the level of the quality variable, in this case a catch rate 

that itself embeds another economic decision variable 

– the effort a recreational fisher devotes to fishing. In 

this example, the quality or number of fish caught per 

hour of effort must be known. Suppose that in the study 

providing the estimated economic benefit, the average 

number of fish caught with an hour of effort before the 

improvement was 2. Thus a 10% improvement means 

that the typical recreationist would catch 0.2 more fish 

with an hour’s effort, implying a unit value of $5 for 

every additional 0.2 fish caught per hour of effort, or 

(assuming a linear relationship in terms of the catch 

rate rather than the proportionate change in this quality 

measure) $25 for every additional fish caught per hour 

of effort. 

Finally, the unit value could be expressed in 

terms of improved fishing trips. Suppose the average 

recreational trip involves 5 hours of fishing over the 

course of a day. Then the improvement of 0.2 fish per 

hour implies an average of one more fish caught during 

a trip. These additional data might be used to imply that 

the improvement makes typical trips yield incremental 

economic benefits of $5 per trip (the value of catching 

0.2 additional fish per hour for a period of five hours). 

There are other ways this estimate could be 

interpreted. These examples are not intended to be 

the only “correct” ones or the best. They illustrate 

that the information on the baseline conditions, the 

measurement of quality, and the measurement and 

terms of use all can affect how a given set of estimates 

is used in a benefits transfer.

For the study site, all three interpretations are simply 

arithmetic transformations of the data describing the 

context for the choices that yield the tradeoff estimates. 

However, the same conclusions do not hold when they 

are transferred to a different situation. Suppose the 

policy site involves a case where we wish to evaluate 

the effects of reducing the entrainment of fish in power 

plant cooling towers. Assume further it is known from 

technical analysis that this regulation would lead to 5% 

improvement in fishing success along rivers affected 

by a rule reducing fish entrainment. Table 4 shows 

the alternative unit value transfers if these areas have 

2000 fishers, each taking about 3 trips per season and 

currently they catch 1 fish per hour.

Clearly these examples deliberately leave out some 

important information. Trips may be different – longer, 

requiring more travel time, or involving different 

features such as different species or related activities. 

These added features are aspects omitted in the example. 

These estimates also do not allow for the possibility that 

fishing success induces current recreationists to take 

more trips or that people who never took trips may start 

taking them after the improvement. Under each of these 

possible outcomes, the sources for error in the transfer 

compound. Even without such details, these simple 

examples illustrate how the aggregate economic benefit 

measures can differ by a factor of four. 

Willingness to pay for an improved catch rate: The challenge of choosing a unit 

value for economic benefits transfer
57

and assumptions of each, would be helpful in increasing 

the likelihood that the most comparable existing 

valuations will be identified. This is a compelling 

rationale for developing databases of valuation studies. 

The establishment and development of a Web-based 

platform for data and models focusing on valuation 

estimates would be very worthwhile. Comparable to 

the Web sites developed and maintained for other largescale social science research surveys such as the Panel 

Study on Income Dynamics (PSID) and the Health 

and Retirement Study (HRS), such a platform could 

expand the ability of Agency analysts to search for the 

most appropriate study cases and to supplement these 

records with related data for transfers. Some efforts 

along these lines are currently underway. These include 

the Environmental Valuation Reference Inventory 

(EVRI), which was developed by Environment Canada 

in conjunction with other agencies including EPA (see 

http://www.evri.ca/), and a database currently being 

developed for recreational use values (see http://www.

cof.orst.edu/cof/fr/research/ruvd/Recreation_Letter.

html ). However, a more systematic effort across a wide 

range of ecosystems services is needed (see Loomis and 

Rosenberger, 2006).

In addition to development and maintenance of a 

comprehensive database of existing valuation studies, 

more original valuation studies across a wider range of 

ecosystem services are needed to increase the Agency’s 

capacity to conduct transfers. The committee urges the 

Agency to support research of this type. This research 

will be most useful if conducted with the explicit 

intention of developing value estimates that EPA can use 

for subsequent transfers. Such an intention can influence 

how the original valuation studies are conducted and 

documented. For example, Loomis and Rosenberger 

(2006) suggest a number of ways of designing original 

studies to facilitate benefits transfer, such as the use 

of objective, quantitative measures of quality changes 

within realistic ranges and the consistent and full 

reporting of project details. These same criteria would be 

appropriate for any value transfer. 

4.4 Conclusions and recommendations 

The valuation approach proposed in this report 

calls for EPA to consider the use of a broader suite of 

methods than EPA has typically employed in the past 

for valuing ecosystems and their services. There is a 

variety of methods that could be used and the committee 

urges EPA to pilot and evaluate the use of alternative 

methods, where legally permissible and scientifically 

appropriate. Some of the methods considered by the 

committee have been used extensively in specific 

decision contexts (e.g., the use of economic methods in 

national rule making or the use of surveys, as described 

in endnote 35), while others are still relatively new and 

in the developmental stages. The methods also differ in 

a number of important ways, including the underlying 

assumptions, the concepts and sources of value they seek 

to characterize, the empirical and analytical techniques 

used to apply them, their data needs (inputs), and the 

metrics they generate (outputs), and the extent to which 

they involve the public. For these reasons, the potential 

for use by EPA in ecological valuation will be different 

for the different methods and in different contexts. The 

Committee advises EPA to:

o Only use methods that are scientifically based and 

appropriate for the particular decision context at hand. 

o Develop a set of criteria to use in evaluating methods 

to determine their suitability for use in specific 

decision contexts. This is an important first step in 

implementing the valuation approach proposed in this 

report

o Explicitly identify relevant criteria to be used in 

determining whether a contemplated values transfer is 

appropriate for use in a specific ecological valuation 

context. Both EPA analysts and those providing 

oversight of their work must take into account the 

differences between study site and policy site to flag 

problematic transfers and clarify the assumptions and 

limitations of the study site results. 

o Support efforts to develop Web-based databases 

of existing valuation studies across a range of 

ecosystem services, with careful descriptions of the 

characteristics and assumptions of each, to assist in 

increasing the likelihood that the most comparable 

existing valuations will be identified. 

o Conduct additional original research on valuation that 

is designed to be used in subsequent value transfers. B
58

5

Cross-cutting issues: deliberative processes, 

uncertainty, and communications

This chapter addresses three topics important to 

multiple stages of ecological valuation: analysis of 

uncertainties related to ecological valuation; communication of ecological valuation information; and the 

role of deliberative processes. 

5.1 Deliberative processes

Deliberative processes, in which analysts, decision 

makers, and/or members of the public meet in facilitated 

interactions, can be useful in estimating and valuing 

the potential effect of EPA actions on ecosystems 

and their related services. Such processes can assist 

at several steps of an assessment, ranging from 

developing conceptual models and determining the 

ecosystem services on which the Agency should focus 

its assessment to valuing those services. For example, 

where the public is not familiar with key ecosystem 

services, deliberative processes can provide the public 

with expert information that may better enable them to 

identify what services are important to them. Similarly, 

where the public is not accustomed to valuing particular 

ecosystem services, deliberative processes may again 

help members of the public estimate the value that they 

would place on those services. Deliberative processes 

also can increase public understanding and acceptance 

of a valuation effort and, where appropriate, permit 

the public to play a more active role in shaping and 

analyzing options.

Two specific types of deliberative processes of potential 

use to EPA in particular valuation efforts are mediated 

modeling and constructed value processes. In mediated 

modeling, analysts work with members of the public to 

develop a model representing a particular environmental 

system of interest, ranging from watersheds or local 

ecosystems to large regions or even the globe (for example, 

Higgins et al., 1997; Cowling and Costanza, 1997; van 

den Belt, 2004). Members of the public participate in 

all stages of the modeling process, from initial problem 

scoping to model development, implementation, and use. 

The resulting model can be used for multiple purposes, 

including determining the ecosystem services that 

are potentially important to the public and evaluating 

alternative scenarios or options of interest. If the model 

is to be used to consider tradeoffs, the model must 

incorporate values drawn from methods described in 

chapter 4. Because of public involvement in the modeling 

process, the model and any results derived from it are 

likely to enjoy buy-in and reflect group consensus. 39

Constructed value processes can help in both 

estimating values and, in some cases, making policy 

decisions. A central premise of constructed value 

processes is that people’s preferences and values for 

complex, unfamiliar goods, such as many ecosystem 

services, are multi-dimensional and that people 

sometimes construct their preferences and values for 

such goods during the process of elicitation. This 

premise contrasts with the premise underlying some 

valuation methods, most notably economic valuation 

methods, that assume preferences are given and that 

values or contributions to well-being can be measured 

using a single metric such as willingness to pay 

or accept.

Constructed value processes can be used either as part 

of a valuation process or directly in decision making. 

In both situations, constructed value processes involve 

a number of steps, including identifying objectives, 

defining the attributes to be used to judge progress 

toward the objectives, specifying the set of management 

options, and measuring changes in relevant attributes 

under the options (Gregory et al., 1993; Gregory et al., 

2001; Gregory and Wellman, 2001). Objectives are 

diverse and often multi-dimensional. Examples include 

maintaining some requisite level of ecological services, 

protecting endangered or threatened species, producing 

particular resources, increasing tourism or recreational 

opportunities, and supplying a sense of pride or awe 

(Gregory et al., 2001). The final output is either a 

judgment about the current state of the system relative 

to an alternative state (if the context is evaluative) or the 

selection or identification of a preferred management 

option (if the context is decision making). Constructed 

value processes draw on inputs from a variety of 

disciplines, including economics, ecology, psychology, 

and sociology. A discussion of the use of decision 

science approaches for ecological valuation appears in 

section 4.2.6.

These deliberative processes, if done in a careful way 

and supported by appropriate resources, can provide 

useful input for valuation by identifying what people 

care about.40 Deliberative processes can be especially 

useful for providing input in valuation situations where 

the public may not be fully informed about ecosystem 

services. Such processes involving science, agency, and 

members of the public can be helpful for getting an idea 

of what an informed public might value. To adequately 

address and incorporate relevant science, however, it 
59

is important that such deliberative processes receive 

sufficient financial and staff resources (SAB, 2001).

5.2 Analysis and representation of 

uncertainties in ecological valuation

5.2.1 Introduction

All aspects of ecological valuation efforts – from 

the estimation of ecological impacts to valuation – 

are subject to uncertainty, regardless of the methods 

used. Assessment of this uncertainty allows for a 

more informed evaluation of proposed policies and 

of comparisons among alternative policy options. For 

each option, decision makers should have sufficient 

information regarding what is known about the 

distribution of possible outcomes and associated values 

in order to take uncertainty into account when they 

make their policy choices. Identifying key uncertainties 

can also provide potentially important insights regarding 

the design of research strategies that can reduce 

uncertainty in future analyses.

When addressing uncertainty in ecological valuation, 

four key questions arise: First, what are the major sources 

of uncertainty and what types of uncertainty are likely to 

arise when using alternative valuation methods? Second, 

what methods are available to characterize uncertainty 

in ecological valuations? Third, how should information 

regarding uncertainty be communicated to decision 

makers? Fourth, what types of new research – data 

collection, improvements in measurement, theory building, 

theory validation, and others – can reduce uncertainty 

for particular sources in specific applications? Section 

5.2.2 briefly describes the major sources of uncertainty in 

the valuation of ecosystems and ecosystem services. The 

overview of specific valuation methods available at http://

yosemite.epa.gov/sab/sabproduct.nsf/WebBOARD/CVPESS_Web_Methods_Draft?OpenDocument discusses 

the uncertainty arising from the use of individual 

methods. Section 5.2.3 then discusses two approaches to 

characterizing uncertainty regarding ecological values: 

Monte Carlo analysis and expert elicitation. Section 5.2.4 

addresses the communication of uncertainty information. 

Section 5.2.5 discusses how EPA can use uncertainty 

analysis to set research priorities.

Historically, efforts to address uncertainty in 

ecological valuations and in all economic benefit 

assessments that are part of regulatory impact analyses 

have been limited. Providing greater information about 

uncertainty is consistent with the need for transparency 

and can improve decision making. In the context of 

regulatory impact analyses, Office of Management and 

Budget Circular A-4 explicitly calls for analysis and 

presentation of important uncertainties. To assess the 

level of confidence to attribute to projections used in 

a valuation, decision makers must know the analyst’s 

judgment of the uncertainty of the valuation and its 

component steps, as well as the assumptions underlying 

the valuation analysis.

5.2.2 Sources of uncertainty in ecological 

valuations

As discussed in chapters 3 and 4, ecological valuation 

entails several analytic steps, each potentially subject to 

uncertainty. These steps include predicting ecological 

impacts of the relevant Agency decision or action, 

predicting the effects of these impacts on ecosystem 

services, and valuing the consequences of these effects.41

Uncertainties in each stage of the analysis are of 

potential importance, and there is no reason – on the 

basis of theory alone – to judge one to be more important 

than the other. Rather, the relative magnitude of the 

uncertainty involved in each step is fundamentally an 

empirical question.

At each stage, uncertainty can arise from several 

sources.42 First, some of the physical processes might 

be inherently random or stochastic. Second, there 

can be uncertainty about which of several alternative 

models of the process best captures its essential features. 

Finally, there are uncertainties involved in the statistical 

estimation of the parameters of the models used in 

the analysis. 

At the biophysical level, for example, any characterization of current or past ecological conditions will 

have numerous interrelated uncertainties. Any effort 

to project future conditions, with or without some 

postulated management action, will magnify and 

compound these uncertainties. Ecosystems are complex, 

dynamic over space and time, and subject to the effects 
60

of stochastic events (such as weather disturbances, 

drought, insect outbreaks, and fires). Also, our 

knowledge of these systems is incomplete and uncertain. 

Errors in projections of the future states of ecosystems 

are thus unavoidable and constitute a significant 

and fundamental source of uncertainty in any 

ecological valuation. 

All social, economic, or political forecasts are also 

based on implicit or explicit theories of how the world 

works, either represented by the mental models of the 

forecasters or by the models underlying the formal 

and explicit methods used in econometric modeling, 

systems dynamics modeling, and other forms of 

modeling. Theories and their expressions as models are 

unavoidably incomplete and may simply be incorrect 

in their assumptions and specifications. These sources 

of uncertainty compound the uncertainty surrounding 

the relevant biophysical relationships and responses to 

policy changes.

Uncertainty also arises in determining the value of 

the predicted ecological responses. The nature and 

interpretation of this uncertainty is different for different 

concepts of value. For example, for concepts of value 

that assume well-defined preferences (such as economic 

value), uncertainty can arise in the estimation of actual 

(“true”) values, for a number of reasons. Valuation 

methods are subject to data and theory limitations, and 

they unavoidably rely on assumptions that introduce 

uncertainty. In addition, analysts are often required 

to apply estimated values to contexts that differ 

from those in which the values were developed, and 

appropriate adjustments might not have been made in 

transferring estimates to different contexts. These types 

of uncertainty in estimating true values can be assessed 

using the methods for probabilistic uncertainty analysis 

discussed below. Alternatively, for concepts of value 

that are based on the premise that preferences must be 

constructed (such as constructed values), uncertainty 

reflects the lack of a “true” underlying value. This type 

of uncertainty differs qualitatively from the uncertainty 

that arises in estimating true but unknown values. As 

a result, it is not meaningful to characterize it using a 

probability distribution function. Rather, in uncertainty 

analysis, the value should be viewed as a parameter that 

can be varied to determine the implications of different 

values for the ranking of alternative policy options (see 

Morgan and Henrion, 1990).

In identifying the types of uncertainty most likely 

to be of concern for individual valuation approaches in 

specific contexts, two issues are relevant: the sensitivity 

of the approach to the potential sources of uncertainty 

listed above, and the magnitude of uncertainty thereby 

generated. The consequence of data limitations can 

be assessed by determining the variation in results 

implied by variations in data. Vulnerability to theoretical 

limitations is more difficult to assess, but can be gauged 

in some cases by comparing predictions based on 

alternative models. 

5.2.3 Approaches to assessing uncertainty 

Probabilistic uncertainty analysis, by its very nature, 

is complex, particularly in the context of ecological 

valuation. The simplest and probably most common 

approach to evaluating uncertainties is some form of 

sensitivity analysis, which typically varies one parameter 

or model assumption at a time and calculates point 

estimates for each of the different parameter values or 

assumptions. The results provide a range of estimates of 

the “true” value, including lower and upper bounds. No 

effort is made to assign probabilities to the calculated 

values or estimate the shape of the distribution of values 

within the range. 

Although sensitivity analysis may be sufficient 

for some simple problems, its use in the context of 

ecological valuation is likely to give an incomplete and 

potentially misleading picture of the true uncertainty 

associated with the value estimates. Due to the 

number of sources of uncertainty in many ecological 

valuations, sensitivity analysis is unlikely to account 

for the implications of all the sources of uncertainty. 

In addition, sensitivity analysis becomes unwieldy 

when the outcomes relevant to the value assessment 

themselves consist of multiple interrelated variables. 

For example, it is extremely difficult at the biophysical 

level to calculate the uncertainty in projecting outcomes 

from a complex ecological system composed of multiple 

interacting variables subject to the influence of external 

stochastic events.

Given the limitations of simple sensitivity analysis, 

other approaches to characterizing uncertainty have 

been developed. These include Monte Carlo analysis 

and the use of expert elicitation. These approaches can 

provide a more useful and appropriate characterization 

of uncertainty in complex contexts such as ecological 

valuation. 

Monte Carlo analysis is an approach to characterizing 

uncertainty that allows simultaneous consideration of 

multiple sources of uncertainty in complex systems. 

It requires the development of a model to predict 

the system’s outputs from information about inputs 

(including parameter values). The underlying inputs that 

are uncertain are assigned probability distributions. A 

computer algorithm is then used to draw randomly from 

all of these distributions simultaneously (rather than 

one at a time, as in sensitivity analysis) and to predict 

outputs that would result if the inputs took these values. 

By repeating this process many times, the analyst can 

generate probability distributions for outputs that are 

conditional on the distributions for the inputs.

Developments in computer performance and software 

have substantially reduced the effort required to conduct 

calculations for a Monte Carlo analysis once input 
61

uncertainties have been characterized. Widely available 

software allows the execution of Monte Carlo analysis in 

common spreadsheet programs on a desktop computer. 

In developing probability distributions for uncertain 

inputs, uncertainty from statistical variation can also 

often be characterized with little additional effort 

relative to that needed to develop point estimates. Much 

of the needed data already will have been collected 

for the development of point estimates (although 

characterizing other sources of uncertainty in inputs can 

require more effort). 

In contrast to sensitivity analysis, Monte Carlo 

analysis provides information on the likelihood of 

particular values within a range, which is essential to any 

meaningful interpretation of that range. Without such an 

understanding, the presentation of a range of possible 

outcomes may lead to inappropriate conclusions. For 

example, a reader may assume that all values within the 

range are equally likely to be the ultimate outcome, even 

though this is rarely the case. Others may assume that the 

distribution of possible values is symmetric. This, also, is 

often not the case.

Because of its ability to characterize uncertainty in a 

more meaningful way, Monte Carlo analysis has become 

common in a variety of fields, including engineering, 

finance, and a number of scientific disciplines. It has 

been useful in policy contexts. EPA recognized as early 

as 1997 that it can be an important element of risk 

assessments (EPA, 1997). Circular A-4, in calling for the 

analysis and presentation of uncertainty information as 

part of regulatory analyses, also notes the potential use 

of Monte Carlo analysis. However, efforts to quantify 

uncertainties through Monte Carlo analyses rarely have 

been undertaken in ecological valuations. More often, 

uncertainty has been addressed qualitatively or through 

sensitivity analysis.

The reliable application of Monte Carlo methods 

requires the specification not only of variances on 

key variables, but also of covariances across the 

variables. Without appropriate covariances, the method 

is unreliable and can lead to biased results. Positive 

covariance increases the spread of results, while negative 

covariances decrease the spread. 

Where Monte Carlo analysis can be reliably used 

in the estimation of ecological values, the analysis is 

unlikely to address all sources of uncertainty. Thus, 

the results will likely understate the range of possible 

outcomes that could result from the relevant public 

policy. Nonetheless, the ranges produced will still 

provide more reliable information about the implications 

of known uncertainties than simple sensitivity analysis. 

In turn, these ranges can better inform judgments 

by policy makers as to the overall implications of 

uncertainty for their decisions. The committee therefore 

urges EPA to move toward greater use of Monte Carlo 

analysis, where feasible, as a means of characterizing 

the uncertainties associated with estimating the value of 

ecological protection.

A variety of expert elicitation methods can also 

provide indications of the amount and nature of 

uncertainty associated with estimates of specific values 

or predictions regarding the impacts of a given activity 

or change (e.g., Morgan and Henrion, 1990; Cleaves, 

1994). In its simplest form, an expert elicitation is a 

single expert’s assessment of the uncertainty of an 

estimate, forecast, or valuation, whether it is based 

on implicit judgment or a more explicit approach 

like the Monte Carlo technique. Policy makers can 

elicit more information from the expert, such as the 

assumptions underlying his or her analysis or the bases 

for uncertainty, to better understand the reliability of the 

expert’s input and the nature of the uncertainty. 

Although an elicitation can rely on a single expert, 

the bulk of expert elicitation methods involve multiple 

experts, which allows for a comparison of their 

judgments and an assessment of any disagreements. If 

the experts are of equal credibility, so that no judgment 

can be discarded in favor of another, the range of 

disagreement reflects uncertainty. If top scientists 

strongly diverge in their estimates, forecasts, or 

valuations, the existence of a high level of uncertainty is 

irrefutable. This relationship, however, is asymmetrical 

because narrow disagreement does not necessarily 

reflect certainty. The experts may all be equally wrong, 

a somewhat common occurrence given that experts 

often pay attention to the same information and operate 

within the same paradigm for any given issue (Ascher 

and Overholt, 1983). When experts interact before 

providing their final conclusions (e.g., by exchanging 

estimates and adapting them to what they learn from one 

another), errors due to incompleteness can be reduced. 

For example, biologists may benefit from the kind of 

information that atmospheric chemists can provide, 

and vice versa. While such interactions run the risk of 

“groupthink” – the unjustified convergence of estimates 

due to psychological or social pressures to come closer 

to agreement (Janis, 1982) – structured group processes 

can help reduce the risk. 

For many expert elicitation methods, translation 

into probabilities is difficult. Simple compilations of 

estimates (e.g., contemporaneous estimates of species 

populations) from different experts can generate a table 

with the range of estimates. However, these compilations 

are unable to convey the degree of uncertainty that each 

expert would attribute to his or her estimate. Including 

confidence intervals can provide this information. 

The SAB has been asked to review a draft Agency 

white paper on expert elicitation and provide advice 

on the utility of using expert elicitation to support 

EPA regulatory and non-regulatory analyses and 
62

decision-making, including potentially in ecological 

valuations. Although EPA has historically focused 

expert elicitations on human health issues, the approach 

may be useful for ecological valuation as well. The 

committee suggests that EPA consider using expert 

elicitation to obtain estimates of parameters and their 

uncertainty for use in Monte Carlo analysis, if suitable 

information about the relevant range for the parameter 

values is not available based on observation (e.g., field 

work or experiments).

5.2.4 Communicating uncertainties in ecological 

valuations

It is important not only to analyze the sources and 

size of uncertainty involved in a valuation but also 

to effectively communicate that uncertainty to both 

decision makers and the public – and in a manner 

that does not overwhelm the recipient and cause 

them to disregard or misinterpret the information. If 

improvements in the analysis of uncertainty do not go 

hand-in-hand with improvements in the communication 

of that uncertainty, the added information can end up 

confounding rather than facilitating good decision 

making (Krupnick et al., 2006). 

In the past, point estimates have been given far 

greater prominence in public documents such as 

regulatory impact assessments and other government 

valuations than discussions of the uncertainty 

associated with them. Uncertainty assessments are 

often relegated to appendices and discussed in a 

manner that makes it difficult for readers to discern 

their significance. This result may be inevitable, given 

that single-point estimates can be communicated 

more easily than lengthy qualitative assessments of 

uncertainty or a series of sensitivity analyses. The 

ability of Monte Carlo analysis to produce quantitative 

probability distributions, however, provides a means 

of summarizing uncertainty that can be communicated 

nearly as concisely as point estimates. If a summary 

of uncertainty is not given prominence relative to an 

estimate itself, decision makers will lose both the 

context for interpreting the estimate and opportunities 

to learn from the uncertainty.

Some resistance to the use of formal uncertainty 

assessments such as through Monte Carlo analysis, and 

to the prominent presentation of the results, may be 

due to the perception that such analysis requires greater 

expert judgment and therefore renders the results 

more speculative.43 Also, some might argue that, given 

the inevitably incomplete nature of any uncertainty 

analysis, prominently presenting its results could 

incorrectly lead readers to conclude that the results 

of an ecological valuation are more certain than they 

actually are. Both concerns are generally unfounded. 

As described above, developing characterizations 

of uncertainty, such as for inputs in a Monte Carlo 

analysis, often simply involves making explicit and 

transparent expert judgments that already must be 

made to develop point estimates for those inputs. To 

the extent that an uncertainty analysis is incomplete 

in its characterization of uncertainty, that fact can be 

communicated qualitatively.

EPA should also consider the use of consistent 

language and graphical approaches in reporting 

on uncertainty in its valuations. Common usage, 

as well as graphical presentation of quantitative 

information regarding uncertainties, can help improve 

communication and understanding of relevant 

uncertainties for both policy makers and interested 

members of the public (Moss and Schneider, 2000). 

Organizations such as the Intergovernmental Panel on 

Climate Change (IPCC) and the Millennium Ecosystem 

Assessment have consciously adopted clear and 

consistent language, as well as graphical approaches, in 

reporting on uncertainty.

5.2.5 Using uncertainty assessment to guide 

research initiatives 

Over time, additional research related to data 

collection, improvements in measurement, theory 

building, and theory validation can reduce the 

uncertainties associated with ecological valuation. For 

example, research can improve our understanding of the 

relationships governing complex ecological systems and 

thereby reduce the uncertainty associated with predicting 

the biophysical impacts of alternative policy options. 

Even stochastic uncertainty can sometimes be addressed 

by initiating research that focuses on factors previously 

treated as exogenous to the theories and models. For 

example, an earthquake-risk model based on historical 

frequency will have considerable random variation if 

detailed analysis of fault-line dynamics is excluded; 

bringing fault-line behavior into the analysis can lead to 

reductions in such uncertainty (Budnitz et al., 1997).

Assessments of the magnitude and sources of 

uncertainty can help to establish research priorities 

and to inform judgments about whether policy changes 

should be delayed until research reduces the degree 

of uncertainty associated with possible changes. 

Enhanced uncertainty analyses can provide decision 

makers with information needed to make better 

decisions. Determining whether the major source 

of uncertainty comes from weak data, weak theory, 

randomness, or inadequate methods can help guide 

the allocation of scarce research funds. Some data 

needs will simply be too expensive to fulfill, and some 

methods have intrinsic limitations that no amount of 

refinement will fully overcome. Uncertainty analysis 

can provide insight into whether near-term progress 

in reducing uncertainty is likely, based on the sources 

of uncertainty and the feasibility of addressing these 

limitations promptly. However, it is important to avoid 

the pitfall of delaying an action simply because some 

uncertainty remains where the benefits of immediate 
63

action outweigh the value of attempting to further 

reduce the uncertainty. Some uncertainty always 

will remain.

5.3 Communication of ecological 

valuation information

The success of an integrated and expanded approach 

to ecological valuation depends in part on how EPA 

obtains information about public concerns during the 

valuation process and then communicates the resulting 

ecological valuation information to decision makers and 

the public (Fischhoff, 2009). Although the committee 

has not extensively discussed the communication 

challenges presented by ecological valuation, it believes 

that generally accepted practices for communication of 

technical information apply to the valuation context. 

Section 5.3.1 discusses general practices of particular 

relevance to valuation. Section 5.3.2 addresses the 

special communication challenges that arise for 

ecological valuation.

Three essential functions of communication in 

valuing the protection of ecological systems and 

services are: 

o Communication among and between technical experts 

and the public within the valuation process itself

o Communication of valuation information by analysts 

to decision makers

o Communication of the results of the valuation and 

decision making processes to interested and affected 

members of the public. 

Although these communication functions may appear to 

be separate steps, they overlap. The success of the overall 

valuation process and any communication step within 

it, for example, depends on understanding how decision 

makers use valuation information. Spokespersons must 

understand how different public groups and experts 

frame valuation issues before they can effectively 

communicate the results of a formal valuation analysis. 

5.3.1 Applying general communication 

principles to ecological valuation

Effective communication should be designed for 

the relevant audience of the valuation information. The 

potential pool of interested parties include decision 

makers, interested and affected members of the public, 

and experts in social, behavioral, and economic sciences 

and ecological sciences. A broad public audience is 

likely to be interested in better understanding the value 

of protecting ecological systems and services. Also 

important is an intermediate audience of analysts, 

who serve as important mediators for valuation 

information through their analyses and activities. 

This latter audience needs to access not only value 

estimates but also technical details and models. To 

support decisions effectively, communications must 

be designed to address a recipient’s goals and prior 

knowledge and beliefs, taking into account the effects 

of context and presentation (Morgan et al., 2002). The 

committee recommends that EPA formally evaluate the 

communication needs of the users of valuations and 

adapt valuation communications to those needs.

As discussed earlier, an effective communication 

strategy also requires interactive deliberation and 

iteration (NRC, 1996). Effective communication of 

values requires systematic interactions with interested 

parties, where the interaction will differ depending 

on the technical expertise and focus of the parties. In 

general, interactive processes are critical for improving 

understanding, although reports (such as EPA’s Draft 

Report on the Environment) are also important, 

especially in the context of assessment. 

Basic guidelines for risk and technical communication 

are generally applicable to communicating ecological 

values. Linear graphs, for example, are likely to convey 

trends more effectively than tables of numbers (Shah and 

Miyake, 2005), and text that incorporates headers and 

other reader-friendly attributes will be more effective 

than text that does not (Schriver, 1989). In developing 

effective communication approaches for ecological 

valuation, EPA can look to guidelines developed for 

risk and technical communication. Two useful examples 

of such guidelines are the communication principles in 

EPA’s Risk Characterization Handbook (EPA, 2000d) 

and the guidelines for effective web sites (Spyridakis, 

2000). The principles in the Risk Characterization 

Handbook include transparency, clarity, consistency, and 

reasonableness. Spyridakis, in turn, provides guidance in 

five categories: content, organization, style, credibility, 

and communicating with international audiences. 

Spyridakis provides a concise table for communicating 

information via Web sites and provides generally 

accepted guidance useful for communication of valuation 

information, including: (a) selecting content that takes 

into account the reader’s prior knowledge; (b) grouping 

information in such a way that it facilitates storing that 

information in memory hierarchically; (c) stating ideas 

concisely; and (d) citing sources appropriately, and 

keeping information up to date.

As in the case of any type of communications, it 

is difficult to predict the effects of communicating 

ecological valuations. Good communications practice 

requires formative evaluation of the communications as 

part of the design process. Testing messages after the 

fact will enable assessments of effectiveness, leading 

to continued improvement in communications (e.g., 

Scriven, 1967; Rossi et al., 2003). The committee 

recommends that EPA evaluate its communication 

of ecological valuations to assess the effects of the 

communication and to learn how to improve upon 

Agency communication practices.
64

5.3.2 Special communication challenges related 

to ecological valuation

Although application of these general communication 

principles will improve communications of ecological 

valuations, special challenges arise in this context. 

First, communicating the value of protecting ecological 

systems and services requires conveying not only value 

information (in terms of metrics such as monetized values 

and rating scales), but also information about the nature, 

status, and changes to the ecological systems and services 

to which the value information applies. The EPA Science 

Advisory Board review of EPA’s Draft Report on the 

Environment (EPA Science Advisory Board, 2005) and 

other reports (e.g., Schiller et al., 2001; Carpenter et al., 

1999; Janssen and Carpenter, 1999) emphasize that people 

need to understand the underlying causal processes in 

order to understand how ecological changes affect the 

things they value, such as ecosystem services.

The causal processes can be conveyed using 

such visual tools as mapped ecological information, 

photographs, graphs, and tables of ecological indicators. 

To the extent that such visual outputs – especially outputs 

from integrated geographic information systems using 

best cartographic principles and practices (Brenner, 

1993) – can be interactive, the outputs will facilitate 

sensitivity analysis that can address audience questions 

about scale and aggregation and may be more effective 

as communication tools. The EPA Science Advisory 

Board has proposed this kind of framework for reporting 

on the condition of ecological resources. EPA’s Draft 

Report on the Environment (EPA, 2002a) and Regional 

Environmental Monitoring and Assessment Program 

reports illustrate a range of representational approaches.44 

Second, the many uses and definitions of the term 

“value” complicate the communication of ecological 

values. The broad usage of the term in this report 

includes all the concepts of value described in Table 1. 

Context and framing can strongly influence how people 

rank, rate, and estimate values (Hitlin and Piliavin, 2004; 

Horowitz and McConnell, 2002), as well as how they 

interpret value-related information (e.g. Lichtenstein and 

Slovic, 2006). 

As discussed elsewhere in this report, value measures 

are required or useful in a variety of regulatory and nonregulatory contexts, ranging from national rule making, 

to site-specific decision making and prioritization 

of environmental actions, to educational outreach in 

regional partnerships. In some cases monetization is 

required, whereas in others (e.g., educational outreach 

by regional partnerships), narratives and visual 

representations of values may play a more important 

role. Little direct evidence exists about how people 

perceive alternative value measures. 

One mechanism for mitigating disconnects when 

reporting ecological values in different metrics is to 

employ an iterative, interactive approach to eliciting, 

studying, and communicating values and tradeoffs, 

where values are represented in multiple ways. Verbal 

quantifiers (e.g., “many” or “very likely”), for example, 

may make technical information more accessible, but the 

wide variability with which these terms are interpreted 

(Budescu and Wallsten, 1995) makes it critical to make 

the underlying numerical information readily available. 

Appropriate use of graphical and visual approaches, 

including geographic information systems, can aid 

interpretation of quantitative information. Visualization 

can facilitate new insights (MacEachren, 1995). 

Third, much remains to be learned about how 

particular representations of non-monetized and 

monetized values, such as narrative, numerical attitude 

ratings, graphics, or other visual information, influence 

decision makers or the public in either value elicitations 

or presentations of cost-benefit analyses. Survey 

and decision research suggest that perceptions – and 

expressions – of values depend on format as well as 

context and specific content.45 For example, including 

graphics in otherwise equivalent sets of information 

demonstrably influences expressed values (Chua, Yates 

and Shah, 2006; Stone et al, 2003). Asking people for 

ecological value in dollars can produce different results 

than using other response scales (e.g., Schlapfer, Schmitt 

and Roschewitz, 2008). 

Finally, in many circumstances, interactive 

communication of ecological valuation information is 

likely to be more effective than static displays. Interactive 

communication allows users to manipulate the data 

or representations of the data, such as with sliders on 

interactive simulations. Interactive visualization has the 

potential to allow users to tailor displays to reflect their 

individual differences and questions. Even with exactly 

the same presentation, people’s understandings of content 

vary because of differences in educational or cultural 

background, and different intellectual abilities. Interactive 

exploration tools give the audience a chance to investigate 

freely the part in which they are interested or about which 

they have questions.

As Strecher, Greenwood, Wang, and Dumont 

(1999) argue, the advantage of interactivity include 

that it supports: active (rather than passive) audience 

participation; tailoring information for individual 

users; assisting the assessment process; and visualizing 

risks under different scenarios (allowing users to ask 

“what if” questions). Interactivity is a good solution 

if the complexity of the visualization has the potential 

to overwhelm users (Cliburn, Feddema, Miller, and 

Slocum, 2002). Interactive visualization nonetheless 

poses challenges as well. 3-D visualization, which has 

become increasingly popular in visualization practice 

(Encarnacao et al., 1994), both necessitates interactivity 

and at the same time challenges it because of the sheer 

computational power required. 
65

5.4 Conclusions and recommendations

Deliberative processes can play an important 

role in the valuation process and the committee 

makes the following recommendations regarding 

their use:

o EPA should consider using carefully conducted 

deliberative processes to provide information about 

what people care about.

o Particular attention should be paid to deliberative 

processes where the public may not be fully 

informed about ecosystem services. Deliberative 

processes involving scientists, agency personnel, and 

members of the public can be helpful for getting an 

idea of what an informed public might value.

o EPA should ensure that deliberative processes receive 

the financial and staff resources needed to adequately 

address and incorporate relevant science and best 

practices.

A recent report of the National Research Council 

also examines public participation in environmental 

assessments and is a useful source for additional 

recommendations on the potential role of deliberative 

processes in the valuation process (NRC, 2008).

Providing information to decision makers and 

the public about the level of uncertainty involved in 

ecological valuation efforts is critical for the informed 

evaluation of proposed policies and alternative 

policy options. The committee makes the following 

recommendations to ensure the effective analysis and 

representation of uncertainties in ecological valuations: 

o In assessing uncertainty, EPA should go beyond simple 

sensitivity analysis and make greater use of approaches, 

such as Monte Carlo analysis, that provide more useful 

and appropriate characterization of uncertainty for the 

complex contexts of ecological valuation. Sensitivity 

analysis is unlikely to account for all sources of 

uncertainty in ecological valuation and can become 

unwieldy when value outcomes consist of multiple 

interrelated variables. EPA should also consider using 

expert elicitation to obtain estimates of parameters and 

their uncertainty for use in Monte Carlo analysis, if 

suitable information about the relevant range for the 

parameter values is not available based on observation.

o The Agency should not relegate uncertainty analyses 

to appendices but should ensure that a summary 

of uncertainty is given as much prominence as the 

valuation estimate itself. EPA should also explain 

qualitatively any limitations in the uncertainty 

analysis. EPA should also explain limitations in the 

valuation exercise due to uncertainties.

o EPA should invest in additional research designed to 

reduce the uncertainties associated with ecological 

valuation through data collection, improvements in 

measurement, theory building, and theory validation. 

Assessments of the magnitude and sources of 

uncertainty can help to establish research priorities 

inform judgments about whether policy changes 

should be delayed until research reduces the degree 

of uncertainty associated with possible changes. 

The Agency, however, should not delay a necessary 

action simply because some uncertainty remains, 

because uncertainty always will remain.

The success of ecological valuations also depends 

on how EPA obtains information about public concerns 

during the valuation process and then communicates 

the resulting ecological valuation information to 

decision makers and the public. To promote effective 

communications, the committee recommends the 

following steps:

o EPA should evaluate the users of valuation 

information and their needs and adopt 

communications that are responsive to those needs.

o In communicating ecological valuation information, 

the Agency should follow basic guidelines for 

risk and technical communication. EPA’s Risk 

Characterization Handbook (EPA, 2000d) provides 

one set of useful guidelines, including transparency, 

clarity, consistency, and reasonableness.

o EPA should evaluate its communication of ecological 

valuations to assess its effects and to learn how to 

improve upon its practices.

o To the extent feasible, the Agency should 

communicate not only value information but also 

information about the nature, status, and changes 

to the ecological systems and services to which 

the value information applies. Visual tools such as 

mapped ecological information, photographs, graphs, 

and tables of ecological indicators can be very useful 

in conveying causal processes.

o Where appropriate, the Agency should employ an iterative, 

interactive approach to communicating values. B
66

6

Applying the approach in three EPA 

decision contexts

This chapter discusses implementing the C-VPESS 

ecological valuation approach in three specific EPA 

decision contexts: national rule making, regional 

partnerships, and site-specific decision making. The 

committee believes that improved ecological valuation in 

each context can contribute to improved policy analysis 

and decisions. The committee examined a number of 

illustrative examples for each decision context and used 

these examples to inform its views about application of 

the approach advocated in this report. 

The discussions below elaborate on the three key 

features of the valuation approach advocated in this 

report as they relate to the specific decision contexts: 

o Identifying and focusing early in the process on the 

impacts that are likely to be most important to people 

o Predicting ecological changes in value relevant terms

o Using multiple methods in the valuation process. 

The discussions are meant to be illustrative rather 

than comprehensive and the exclusion of a particular 

method from discussion in a specific context is not 

intended to suggest inappropriateness. Note that the 

general principles and concepts used in the discussions 

below are described in more detail elsewhere in this 

report (see, for example, chapter 4 and descriptions of 

valuation methods and survey issues and best practices, 

links available on the SAB Web site at http://yosemite.

epa.gov/sab/sabproduct.nsf/WebBOARD/C-VPESS_

Web_Methods_Draft?OpenDocument).

6.1 Valuation for national rule making

6.1.1 Introduction

This section examines the application of the 

expanded, integrated approach to ecological valuation 

in the context of national rule making. Executive 

Orders and implementation guides often specifically 

require assessment and analysis of the benefits and 

costs of national rules to follow prescribed economic 

methods. Thus, this section is focused on the application 

of valuation using economic methods. In addition, it 

discusses the role that the other methods described in 

chapter 4 can play in this context. As background for this 

discussion, the committee examined three examples of 

previous Agency economic benefit assessments: 

o The Agency’s assessment for the final effluent 

guidelines for the aquaculture industry (EPA, 2004a)

o The Agency’s assessment for the 2002 rule making 

regarding concentrated animal feeding operations 

(CAFOs) (EPA, 2002b; chapter 2 also discusses this 

benefit assessment)

o The prospective analysis of the benefits of the Clean 

Air Act Amendments of 1990 (EPA, 1999).46

Brief descriptions of the three benefit analyses are 

presented later in this section. These examples provide 

insights reflected in the discussion and recommendations 

throughout this section.

6.1.2 Valuation in the national rule making 

context

As noted previously, valuation by EPA in the 

national rule making context is typically subject to 

constraints imposed by statute, executive order, and/

or guidance from the Office of Management and 

Budget (OMB). Most of the environmental laws 

administered by the Agency require that regulations 

such as environmental quality standards and emissions 

standards be based on criteria other than economic 

benefits and costs. In some cases, the legislation 

explicitly precludes consideration of costs or benefits 

in the standard-setting process. For example, under the 

Clean Air Act, primary ambient air quality standards 

for criteria air pollutants must be set to protect human 

health with an adequate margin of safety. Even where 

a law, such as the Safe Drinking Water Act, allows 

consideration of benefits and costs, adherence to a strict 

“benefits must exceed costs” criterion is not required. 

However, even when national EPA rules are 

not determined by a strict benefit-cost criterion, 

assessments of the benefits and costs of EPA actions, 

conducted under prescribed procedures, can be 

important for a number of reasons. First, Executive 

Order 12866 (as amended by Executive Order 13422), 

requires federal agencies to “assess both the costs 

and the benefits of the intended regulations, and ... 

propose or adopt a regulation only upon a reasoned 

determination that the benefits of the intended 

regulation justify its costs” (Executive Order 12866, 

October 4, 1993). These assessments are commonly 

referred to as regulatory impact assessments (RIAs). 

They generally evaluate, in economic terms, the 

form and stringency of the rules that are established 

to meet some other objective, such as protection of 

human health.
67

Second, in some cases, an assessment of economic 

benefits and costs can be mandated by law. For example, 

Section 812 of the Clean Air Act Amendments of 1990 

requires the Agency to develop periodic reports to 

Congress that estimate the economic benefits and costs 

of various provisions of the Act. Finally, the benefit 

and cost estimates developed in national rule making 

can help in setting research or legislative priorities. In 

summary, a complete, accurate, and credible analysis 

of the benefits and costs of a given rule can have broad 

impacts, even if the analysis does not determine whether 

a currently proposed rule should be promulgated. 

In conducting RIAs, EPA is subject to requirements 

specified by OMB guidance, and all EPA benefit 

assessments are subject to OMB oversight and approval. 

As noted in chapter 2, OMB’s Circular A-4 (OMB, 

2003) makes it clear that Executive Order 12866 

requires an economic analysis of the benefits and costs 

of proposed rules conducted in accordance with the 

methods and procedures of standard welfare economics. 

In the context of national rule making, the terms benefit 

and cost thus have specific meanings. To the extent 

possible, EPA must assess the benefits associated with 

changes in goods and services as the result of a rule, 

judged by the sum of the individuals’ willingness to 

pay for these changes. Similarly, the costs associated 

with regulatory action are to be evaluated as the losses 

experienced by people, and measured as the sum of 

their willingness to accept compensation for those 

losses. EPA must begin the analysis by specifically 

describing environmental conditions in affected areas, 

both with and without the rule. EPA must then value 

these changes based on individual willingness to pay and 

to accept compensation, aggregated over the people (or 

households) experiencing them. Although other valuation 

methods described in chapter 4 may yield monetary 

estimates of value, monetizing values using multiple 

methods and then aggregating the resulting estimates 

would mean combining estimates that are based on 

quite different theoretical constructs, as well as diverse 

underlying assumptions. Thus, for both theoretical and 

empirical consistency – as well as compliance with 

OMB guidance – monetization of benefits in the context 

of an RIA should be based on economic valuation. 

Circular A-4 recognizes that it may not be possible 

to express all benefits and costs in monetary terms. In 

these cases, it calls for measurement of these effects in 

biophysical terms. If that is not possible, there should 

be a qualitative description of the benefits and costs 

(OMB, 2003, p. 10). Circular A-4 is clear about what 

should be included in regulatory analyses, but it does 

not preclude the inclusion of information drawn from 

non-economic valuation methods. Nonetheless, it implies 

that when conducting ecological valuation in the context 

of national rule making, EPA must seek to monetize 

benefits and costs using economic valuation methods as 

much as possible. 

Although economic valuation methods are welldeveloped and there is a large literature demonstrating 

their application, applying these methods to the 

ecological benefits of a national-level rule raises 

significant challenges. A key challenge is the difficulty 

of deriving a national estimate of the effect of an EPA 

rule on ecosystems and the services derived from 

these ecosystems. Such a national estimate requires 

information about changes in stressors resulting from 

the action, as well as information about how the 

changes in stressors will affect ecosystems and the flow 

of services nationally. In many rule-making contexts, 

predicting the changes in stressors is difficult. Often, 

the rule prescribes adoption of a particular technology 

or a particular behavior (e.g., adoption of best 

management practices) rather than a specific change in 

stressors (e.g., discharge limits). The aquaculture rule 

associated with the Clean Water Act, described in text 

box 1, provides an example. In those cases, to estimate 

associated benefits, EPA must predict the changes in 

stressors that would likely result from the required 

behavioral change. 

A rule will often involve many stressors with 

complex interactions, which greatly complicates the 

development of quantitative estimates of changes in 

stressors. The CAFO rule, described in chapter 2 and 

below, is an illustration.

Changes must also be defined relative to a baseline, 

and few national-level databases useful for this purpose 

exist. For example, in the RIA for the aquaculture rule, it 

was difficult to quantify the changes in stressors because, 
68

in some cases, baseline data on stressor levels were not 

available. 

Even if changes in stressor levels can be predicted 

at the national level, mapping these into nationallevel changes in ecosystem characteristics or services 

using ecological production functions is generally 

very difficult. There may be a long chain of ecological 

interactions between the stressors and the ecosystem 

services of interest – and often many of links in that 

chain are not fully understood by scientists, particularly 

at the level required for comprehensive national 

analysis. Scientific knowledge is especially lacking 

on the ecological impacts of substances such as heavy 

metals, hormones, antibiotics, and pesticides. However, 

these substances can have important and far-ranging 

impacts at the national level. In addition, the nature and 

magnitude of impacts can be very site-specific because 

Text box 1 – Valuation and the aquaculture effluent guidelines

Title III of the Clean Water Act gives EPA authority to issue effluent guidelines that govern the setting 

of national standards for wastewater discharges to surface waters and publicly owned treatment works 

(municipal sewage treatment plants). The standards are technology-based, i.e., they are based on the 

performance of available treatment and control technologies. The proposed effluent guidelines for the 

concentrated aquatic animal production industry (aquaculture) would require that all applicable facilities 

prevent discharge of drugs and pesticides that have been spilled. In addition, facilities must minimize 

discharges of excess feed and develop a set of systems and procedures to minimize or eliminate discharges of 

various potential environmental stressors. The rule also includes additional qualitative requirements for flowthrough and recirculating discharge facilities and for open water system facilities (EPA, 2004a).

The Agency identified the following potential ecological stressors that might be affected by the rule: 

solids; nutrients; biochemical oxygen demand from feces and uneaten food; metals (from feed additives, 

sanitation products, and machinery and equipment); food additives for coloration; feed contaminants (mostly 

organochlorides); drugs; pesticides; pathogens; and introduction of non-native species. Some of these (e.g., 

drugs and pathogens) were thought by the Agency to be very small in magnitude and not require further 

analysis. To this list, C-VPESS would add habitat alteration from changes in water flows. 

For most of these stressors, it is not possible to specify the change that would result from the rule for two 

reasons. First, the rule called for adoption of “best management practices” rather than imposing specific 

quantitative maximum discharge levels. Second, for most of these stressors, baseline data on discharges in the 

absence of the rule were not available.

The Agency analyzed the effects of the rule on dissolved oxygen, biochemical oxygen demand, total 

suspended solids, and nutrients (nitrogen and phosphorus). There appear to have been three reasons why the 

remaining endpoints were not quantified: 

o The Agency lacked data on baseline stressor levels.

o The rule called for adoption of “best management practices” rather than imposing specific quantitative 

maximum discharge levels, and the Agency lacked information on how these requirements would change 

the levels of stressors. 

o The Agency did not use a model capable of characterizing a wide range of ecological effects. The 

Agency used QUAL2E rather than the available AQUATOX model. The choice of QUAL2E appears to 

have been driven largely by the ability to link its outputs with the Carson and Mitchell valuation model 

(1993). 

The Agency estimated benefits for recreational use of the waters and non-use values. To estimate these 

values, the Agency estimated changes in six water quality parameters for 30-mile stretches downstream from 

a set of representative facilities and calculated changes in a water quality index for each facility. The Agency 

then used an estimated willingness-to-pay function for changes in this index taken from Carson and Mitchell. 

Carson and Mitchell had asked a national sample of respondents to state their willingness to pay for changes 

in a water quality index that would move the majority of water bodies in the United States from one level 

on a water quality ladder to another, resulting in improvements that would allow for boating, fishing, and 

swimming in successive steps. The aggregate willingness-to-pay for the change in the water quality index for 

each representative facility was then used to extrapolate to the population of facilities of each type affected by 

the rule.
69

they vary substantially both within and across regions 

of the country. As a result, predictions of biophysical 

impacts in one region generally cannot readily be 

transferred to other regions where the characteristics 

of the relevant ecosystems, as well as the affected 

population, are different. 

Even if the national impact of the rule can be 

estimated, the Agency must then seek to monetize 

the value of that impact using economic valuation 

techniques if possible. Because EPA generally does not 

have the time or resources required to conduct significant 

original economic valuation research for specific national 

Text box 2 – Valuation and the CAFO effluent guidelines

In December 2000, in response to structural changes in the industry, EPA proposed a new rule to govern 

discharges from CAFO facilities. The new rule, which was finalized in December 2003, requires facilities 

to implement comprehensive nutrient management plans designed to reduce the runoff of pollutants from 

feedlots and from the land application of manure. The rule focuses on the largest operations that represent the 

greatest environmental threats. 

Manure from livestock operations produces a variety of potential pollutants that can migrate to ground 

water, streams, rivers, and lakes. These pollutants include nitrogen, phosphorus, sediments and organic 

matter, heavy metals, salts, hormones, antibiotics, pesticides, and pathogens (over 150 pathogens found 

in manure are human health risks). CAFO facilities also release a variety of gases and material into the 

atmosphere including particulates, methane, ammonia, hydrogen sulfide, odor-causing compounds, and 

nitrogen oxides. 

Of the water-polluting materials covered in the CAFO rule, excess nutrients can directly affect human 

water supply through excess nitrates, adversely affect agriculture through excess salts in irrigation waters, 

and cause eutrophication of water bodies, anoxia, and toxic algal blooms. These latter effects can result in 

fundamental changes in the structure and functioning of aquatic ecosystems, including cascading effects that 

reduce water quality and species diversity. Uncontrolled releases of animal wastes have resulted in massive 

fish mortality.

Pathogens in polluted waters are a health hazard, both directly and through the food chain. The potential 

human health impacts of antibiotics and hormones in wastes have not been well identified but are of concern. 

Of all the potential environmental impacts, the CAFO economic benefits analysis focused to a large extent 

on the nutrient runoff from land where manure has been applied and the economic benefits that would accrue 

from the manure management requirements of the CAFO rule. To estimate the benefits, the analysis utilized 

the GLEAMS model (Groundwater Loading Effects of Agricultural Management Systems). The outputs 

include nutrients, metals, pathogens, and sediments in surface runoff and ground-water leachate. This model 

was applied to model farms of different sizes, animal types, and geographic regions. From this model the 

reductions in pollutant loading of nutrients, metals, pathogens, and sediments were estimated for large- and 

medium-sized CAFO. 

Seven categories of economic benefits were estimated: water-based recreational use (by far the largest 

category), reduced numbers of fish kills, increased shellfish harvest, reduced ground water contamination, 

reduced contamination of animal water supplies, reduced eutrophication of estuaries, and reduced water 

treatment costs. Reductions in fish kills and animal water supply contamination were valued using 

replacement cost. Increased shellfish harvests were valued using estimated changes in consumer surplus. 

Water-based recreation was valued using the Carson and Mitchell (1993) study. Ground water contamination 

was valued using economic benefits transfer based on a set of stated-preference studies. There was no 

national estimate of the economic benefits of reduced eutrophication of estuaries, but there was a case study 

on one estuary focusing on recreational fishing and using economic benefits transfer based on revealedpreference random utility models.

A number of potential impacts were not included in the economic benefits analysis relating to the water 

quality improvements of the rule including human health and ecological impacts of metals, antibiotics, 

hormones, salts, and other pollutants; eutrophication of coastal and estuarine waters due to nitrogen 

deposition from runoff; nutrients and ammonia in the air; reduced exposure to pathogens due to recreational 

activities; and reduced pathogen contamination of drinking water supplies. These impacts were not monetized 

mainly because of a lack of models and data to quantify the impacts and, in some cases, the lack of methods 

to perform the monetization. 
70

assessments of benefits and costs, the Agency typically 

must rely heavily on benefits transfer, i.e., using results 

from previous studies and adapting those results for 

the specific valuation context of interest. However, 

most of the previous ecological valuation studies that 

might serve as study sites for benefits transfer are not 

national in scope and generally have focused on only 

a limited number of ecosystem characteristics or 

services. Because they were designed for different 

purposes, previous studies have not selected either 

the study sites or the assessed services to facilitate 

national assessments of ecological benefits that might 

be important in a rule making context. Rather, they 

usually have involved specialized case studies selected 

because data were available or a specific change was 

readily observable. In addition, the studies generally 

measure tradeoffs for small, localized changes affecting 

a limited regional population.47

Perhaps the most relevant area for which considerable 

economic valuation has been conducted is recreation 

demand. Many economic valuation studies have estimated 

the recreation benefits stemming from hypothetical 

or predicted changes in environmental characteristics 

of recreation sites. For example, several studies have 

used random utility models (a revealed-preference 

approach) to link physical descriptors of water quality to 

recreation behavior and estimate the willingness-to-pay 

or willingness-to-accept per recreational trip for a given 

change in water quality. 48 However, these studies value 

only localized changes and cannot be directly used to 

provide national-level benefit estimates.

Previous studies have also estimated the benefits 

associated with changes in ecological services that 

affect the well-being of homeowners living near the 

ecological systems. Examples include water regulation, 

flood control, and the amenities associated with healthy 

populations of plants and animals. The willingness of 

residents to pay for these services is capitalized into 

housing prices and can be estimated using hedonic 

property value methods. Examples illustrating this 

approach to valuing ecosystem services include Leggett 

and Bockstael (2000), Mahan et al. (2000), Netusil 

(2005), and Poulos et al. (2002). Estimates from such 

studies could also be candidates for use in an economic 

benefits transfer. However, as with the recreation studies, 

these studies are almost exclusively local rather than 

national in scope, which makes extrapolation to nationallevel benefit assessments difficult. Some exceptions that 

do provide national-level benefits assessments are Chay 

and Greenstone, 2005, and Deschenes and Greenstone, 

2007. If sufficient high-quality original valuation studies 

are available, it might be possible to combine estimates 

of economic benefits from local studies in meta-analyses 

for use in benefits transfer (e.g., Smith and Pattanayak, 

2002; Bergstrom and Taylor, 2006; and chapter 4). 

However, using meta-analysis to estimate benefits at a 

specific policy site can raise a number of issues. These 

include issues of consistency and those related to the 

scope of the resource changes valued in the original 

studies (e.g., whether they valued localized changes or 

changes at the national level). A meta-analysis of studies 

that valued localized changes can, at best, generate 

values for similar localized changes. It cannot generate 

values for changes that would occur at the national level 

unless individuals care only about localized effects. 

Therefore, even structurally based meta functions from 

local studies generally do not provide a functional 

relationship that can be used to estimate benefits at the 

national level, based on characteristics of the affected 

population. For example, using a meta function of unit 

values for a localized ecosystem change to predict 

average willingness-to-pay per person (e.g., evaluating 

the meta function using mean population characteristics) 

and then multiplying the resulting value by the relevant 

national population would generally not provide a valid 

measure of national-level benefits. 

Despite the challenges described, the Agency has, in 

some cases, generated defensible estimates of economic 

benefits at the national level for a limited set of ecosystem 

services. For example, in the prospective benefit 

assessment of the Clean Air Act Amendments, described 

in text box 3, EPA used the best available economic and 

ecological models to estimate commercial forestry and 

agricultural benefits. However, in other cases, the Agency’s 

efforts to provide monetized ecological benefit estimates 

using benefits transfer have generated benefit estimates that 

are much less defensible or have led the Agency to focus 

on a very limited set of ecosystem services. 

Chapter 2 of this report addresses the benefit 

assessment for the CAFO rule and highlights the 

committee’s concern about EPA’s approach. As discussed 

in that chapter, EPA estimated recreational benefits using 

a water quality survey conducted in the early 1980s 

(Carson and Mitchell, 1993). The principal advantage of 

this approach was that it utilized a national survey and 

presented a simple willingness-to-pay relationship for 

improvements in water quality that allowed nationallevel benefits to be estimated relatively quickly without 

new research. This study was also used in the assessment 

of EPA’s aquaculture rule (in text box 1). However, in 

addition to being more than 20 years old, the survey 

was not designed for those uses. The water quality 

index employed in the study was highly simplified and 

only reflected ecological services related to fishing, 

swimming, and boating. Thus, the benefits transfers were 

considerably outside the domain of what was envisioned 

in the design of the original survey and what could have 

been known by the people who responded to it in the 

early 1980s. 

The desire to use value estimates from the Carson and 

Mitchell study apparently also influenced the choice of 

ecological models used to predict water quality impacts. 
71

In both the CAFO and aquaculture assessments, EPA 

chose to use the QUAL2E water quality model (Barnwell 

and Brown, 1987) apparently because it could readily be 

linked to this valuation study. Although this model can 

estimate the interactions among nutrients, algal growth, 

and dissolved oxygen, it is not capable of ascertaining 

the impacts of total suspended solids, metals, or organics 

on the benthos and the resulting cascading effects on 

aquatic communities that might have important water 

quality impacts. 

Text box 3 – Ecological benefit assessment as part of the prospective study of the economic 

benefits of the Clean Air Act Amendments

The first prospective benefit-cost analysis mandated by the 1990 Clean Air Act Amendments included 

estimates of the ecological benefits resulting from the expected reductions in air pollutants (EPA, 1999). 

The Agency included qualitative discussions of several potential ecological effects of atmospheric pollutants 

based on a review of the peer-reviewed literature (chapter 7, and pp. E-2 to E-9), including acid deposition, 

nitrogen deposition, mercury and dioxins, and ozone.

The Agency used two criteria to narrow the scope of work for quantification of impacts: First, the endpoint 

must be an identifiable service flow. Second, a defensible link must exist between changes in air pollution 

emissions and the quality or quantity of the ecological service flow, and quantitative economic models must 

be available to monetize these damages.

The Agency provided estimates of three categories of economic benefits related to ecosystems based on 

standard economic models and methods: a) benefits to commercial agriculture associated with reductions in 

ozone; b) benefits to commercial forestry associated with reductions in ozone; and c) benefits to recreational 

anglers in the Adirondacks lake region due to reductions in acidic deposition.

For agriculture, the Agency used crop-yield loss functions to estimate changes in yields, which were then 

fed into a model of national markets for agricultural crops (AGSIM) to estimate changes in consumers’ and 

producers’ surplus. 

For commercial forestry, the PnET-II model was used to estimate the effects of elevated ambient ozone 

on timber growth. The PnET-II model relates ozone-induced reductions in net photosynthesis to cumulative 

ozone uptake. Analysis of welfare effects used the U.S. Department of Agriculture Forest Service Timber 

Assessment Market Model (EPA, 1999, pp. 92-93) to translate the increased tree growth from a reduction in 

ozone to an increase in the supply of harvested timber and computed the changes in consumers plus producer 

surplus based on the associated price changes. Because of the lack of data and relevant ecological models, the 

Agency did not quantify or monetize aesthetic effects, energy flows, nutrient cycles, or species composition 

in either commercial or non-commercial forests. 

To estimate the recreational economic benefits of reducing acid deposition in Adirondacks lakes, the 

Agency used a published study of recreational angling choices of households in New York, New Hampshire, 

Maine, and Vermont (Montgomery and Needelman, 1997). Measured pH of lakes was used as an indicator 

of the level of ecological services from each lake. The literature on the economics of recreational angling 

shows that likelihood of success as measured by numbers of fish caught is a major determinant of demand 

for recreational angling (Phaneuf and Smith, 2005; Freeman, 1995). To the extent that populations of target 

species are correlated with pH levels, pH is a satisfactory proxy for fish populations and angling success 

rates. There was no attempt to quantify other ecosystem services of water bodies likely to be affected by acid 

deposition. 

The Agency also presented an estimate of the economic benefits of reducing nitrogen deposition in coastal 

estuaries along the east coast of the United States. Although the Agency was able to estimate changes in 

nitrogen deposition for the three estuaries covered in the prospective analysis, it was not able to establish the 

necessary ecological linkages to quantify the effects on recreational and commercial fishing. The assumed 

avoided costs were the costs of achieving equivalent reductions in nitrogen reaching these water bodies through 

control of water discharges of nitrogen from point sources in these watersheds. As noted in chapter 4 of this 

report, avoided cost is a valid measure of economic benefits only under certain conditions, including a showing 

that the alternative whose costs are the basis of the estimate would actually be undertaken in the absence of 

the environmental policy being evaluated. Because it was not possible to make this showing in the case of 

controlling nitrogen deposition, the Agency chose not to include the avoided cost benefits in its primary estimate 

of economic benefits, but only to show them as an illustrative calculation.
72

The committee also notes that EPA has concentrated 

on a limited set of ecosystem services because of 

its focus on monetization. Estimating some of the 

ecological benefits of a given rule certainly provides 

better information than not estimating any of them, and 

the committee commends the Agency for its efforts to 

provide some information about ecological benefits. In 

addition, if the benefit estimates derived from a limited 

set of services are sufficiently large to “justify” the costs 

(as required by Executive Order 12866) and the only 

objective of the analysis is to make this determination, 

omitting detailed consideration of other impacts can 

save scarce resources without affecting the conclusion. 

However in some cases, the benefits from a limited 

set of services might not justify the costs, but a more 

complete assessment of benefits very well might. In 

these cases, focusing on only a subset of services could 

lead to incorrect conclusions or inferences about relative 

benefits and costs. Perhaps more importantly, even if 

estimated benefits based on a limited set of services are 

sufficient to justify costs, a more complete assessment 

of benefits could provide useful information about 

whether a more stringent rule is warranted. In addition, 

representing the benefits from a limited set of ecosystem 

services as the total economic benefits associated with a 

rule can be misleading and confusing to policy makers 

and the public if they have a broader conception of the 

rule’s possible benefits. 

6.1.3 Implementing the proposed approach

While recognizing the many challenges posed by 

ecological valuation in the context of national rule 

making, the committee believes that the valuation 

approach proposed in this report can be usefully 

applied in this context and can improve on the Agency’s 

current approach to these challenges. Implementing the 

proposed approach would entail some short-term steps 

that could be incorporated into EPA’s valuation processes 

using the existing knowledge base, as well as some 

longer-term strategies for research and data/method 

development that would improve ecological valuation for 

national rule makings in the future.

6.1.3.1 Implementation in the short run 

A key premise of the committee’s approach is 

that valuation should include early identification 

of the socially important impacts of an EPA rule. 

This requires information about both the potential 

biophysical effects of the Agency’s actions and the 

ecological services that matter to people. As discussed 

in chapter 3, the Agency should develop a conceptual 

model early in the valuation process and then use that 

model to guide the valuation process. Conceptual 

models can allow the Agency to take a broad view 

of the complexities involved in ecological changes 

and ensure that impacts that are potentially important 

to people are included in the analysis. It should be 

standard practice for the Agency to develop such a 

conceptual model before other analytical work begins 

on an ecological benefit assessment. 

Development of a conceptual model requires both 

an interdisciplinary team of experts and input about 

what matters to the public. To determine the relevant 

ecological effects to include in the conceptual model, 

EPA can draw on technical studies of impacts and their 

magnitudes. It can also solicit expert opinion regarding 

the physical and biological effects of a regulatory 

change. Figure 4, developed by the committee, illustrates 

that CAFOs can affect ecosystems in multiple ways 

and at multiple scales. The environmental effects of 

CAFOs extend beyond water quality impacts. For 

example, CAFOs generate interactive pollutants that 

affect air as well as water. The figure, however, does 

not provide a full conceptual model that maps EPA 

actions or decisions to potential ecological responses 

and ecosystem services. Instead, it provides a starting 

point for constructing a comprehensive overview of the 

potential ecological services that might be affected by an 

EPA rule. 

The conceptual model should reflect not only 

ecological science but also information about the 

changes that are likely to be of greatest importance to 

people. This information cannot be derived deductively. 

Rather, it requires input about public concerns and 

preferences. Although Circular A-4 requires use of 

economic valuation methods to estimate benefits and 

costs, at this early stage, EPA can use a variety of 

methods to identify the public concerns associated with a 

given rule. For example, EPA can glean this information 

from the existing knowledge base or actively solicit it 

through an interactive process. Approaches using the 

existing knowledge base might include:

o Inventorying the reasons invoked in similar rulemaking processes in other jurisdictions (e.g., state 

and local) 

o Inventorying the concerns expressed in public 

hearings at various governmental levels or in previous 

participatory processes through, for example, content 

analysis of transcripts (perhaps with weightings based 

on the frequency of concerns raised)

o Studying previously conducted surveys providing 

information about related public concerns

o Analyzing relevant initiatives, referenda, or 

community decisions revealing preferences for 

various types of ecosystem services or the avoidance 

of various risks 

An important consideration in identifying socially 

important impacts is the extent to which the public 

understands the role that ecosystems play in providing 

services that contribute to human well-being. When 

relying on information from public expressions of 

preferences (e.g., surveys, public hearings, community 
73

decisions) to identify socially important impacts, 

the Agency should assess whether the public, when 

expressing preferences, was aware of and understood the 

ecosystem services sufficiently well to provide informed 

responses. Many ecosystem services – although well 

known to the scientific community – are little known 

or misunderstood by the general public (Weslawski 

et al., 2004). This is more likely for intermediate 

services than final services. For example, the public 

generally does not understand or appreciate the full 

chain of connections described in figure 4. Nor does 

the public typically understand the organisms and 

processes involved in breaking down waste products 

or the services provided by those processes. While the 

public need not understand all of the underlying science 

and associated linkages, they need to understand 

the magnitude and nature of changes they are being 

asked to value. Lack of public understanding can be 

more problematic in national-level analyses, where 

ecological impacts and vulnerabilities can vary 

substantially across locations. For this reason, it is 

important that queries regarding preferences and values 

be framed in terms of impacts that people understand 

and can value (see discussions in sections 2.1.4 and 

3.3.2). 

EPA can also at least partially mitigate information 

problems in national assessments by seeking 

public input through an interactive or participatory 

process. Such a process could take a number of 

forms, including focus groups, active solicitation 

of comments on a preliminary list of potentially 

important ecosystem services, or mediated modeling. 

A participatory process could also educate the 

participants about the underlying science and thus 

increase the likelihood that individuals expressing 

value judgments are well-informed. Although time 

and resource constraints may preclude use of a 

participatory process in many contexts, the committee 

Figure 4: Ecological impacts of CAFOs at multiple scales

Fertilizers

Pesticides Crop

Air

Water

Soil

Wild

Fish

Harvest

Local

National

Regional Global

Treatment

Biological

Engineering

Incineration

Chemical

NH3

NOX

VOC

Pm10

Odor

N2

O

CH4

H2S

Pm2.5

Nitrate

Sediments

Antibiotics

Heavy Metals

Salts

Phosphate

Hormones

Pesticides

Pathogens

Organic Matter

Captured Energy

Fertilizer

Losses

Losses

Losses

Non Point Source

Pollution

Residues

Habitat

Impacts

Feed

Supplements

Feed

Export

AFO

Air

Water

Soil
74

suggests that EPA pilot the use of such processes (e.g., 

by holding open meetings with the public and Agency 

staff) to aid in identifying ecological changes that are 

important both biophysically and socially.

When properly conducted, the development of the 

conceptual model should identify a list of ecosystem 

effects or changes in ecosystem services that are 

potentially important to people, as well as the associated 

complexities, interactions, variability, and sources 

of uncertainty, including gaps in information. The 

Agency should ensure that the call for monetization, 

coupled with the need to generate national-level benefit 

estimates, does not unduly restrict the types of ecological 

changes considered in the benefit assessment or lead to 

inappropriate application of economic valuation methods 

or benefits transfer. 

Toward this end, once EPA has identified a list 

of potentially important changes in ecosystems and 

their services, the Agency should assess the extent to 

which each of these can be monetized, quantified, or 

characterized. More specifically, the Agency should 

categorize potentially important effects identified in the 

conceptual model into five categories:

o Category 1: Effects for which benefits can be assessed 

and monetized using available ecological models and 

appropriate economic valuation methods, including 

benefits transfer.

o Category 2: Effects for which benefits cannot be 

monetized, but that can be quantified in biophysical 

terms using available ecological models and for 

which some indicator(s) of economic benefits exist.

o Category 3: Effects that can be quantified in 

biophysical terms but for which no indicators of 

economic benefits exist.

o Category 4: Effects that can be qualitatively described 

and generally related to benefits based on available 

ecological and social science, even if they cannot be 

quantified.

o Category 5: Effects that are likely to generate 

important non-economic values.

Categories 1 through 4 are designed to provide as 

much information as possible about economic benefits, as 

required by Circular A-4 (p.18). They thus fit conceptually 

within a benefit-cost framework. Category 5 corresponds 

to supplemental information about other values that 

could be of interest to policy makers and the public but 

are not based on the principles that underlie benefit-cost 

analysis. Thus, category 5 is conceptually distinct from 

categories 1-4. Note that some effects might fall into 

multiple categories. For example, a rule that affects a 

given fish population might have benefits not only for 

commercial fishing that can be monetized (category 1) 

but also cultural value to native populations that could be 

included in category 5.

In compliance with the OMB circular, EPA should try 

to include benefits in category 1 to the extent possible, 

and it is important for EPA to support the research 

needed to include more benefits in that category in the 

future. Nonetheless, explicit identification of benefits 

in categories 2 through 4 can help ensure that these 

effects receive sufficient attention in benefit assessments, 

even though they cannot be monetized with currently 

available data and models.

The analysis of economic benefits and other values 

under the committee’s proposed approach differs 

across these different categories. With regard to the 

first category, estimation of monetized benefits requires 

three elements: a prediction of the change in relevant 

stressors resulting from the rule, a prediction of how 

that change will affect the ecosystem and ultimately 

the provision of ecosystem services, and an estimation 

of the benefits associated with the effect. To do this, 

the conceptual model must be linked with one or more 

ecological models that capture the essential linkages 

embodied in the conceptual model and are parameterized 

to reflect the range of relevant scales and regions. These 

ecological models must generate outputs that can be 

used as inputs in a benefits transfer or other economic 

valuation method. Because many existing ecological 

models do not satisfy this requirement, in the short run 

this requirement represents a significant constraint on 

the ecosystem effects for which benefits can be assessed 

and monetized and highlights the need for research to 

develop new ecological models.

Although in principle economic valuation methods 

can fully capture the benefits associated with changes 

in ecological systems and services, in practice there 

are significant limitations that can make this very 

difficult, particularly at the national level. However, 

even when benefits cannot be monetized using available 

ecological models and reliable information about 

economic values, the associated ecological changes 

may still be quantifiable. Here again, EPA should focus 

on quantifying all of the ecological changes that are 

potentially important to people. If EPA is not limited 

to effects for which the benefits can be monetized, 

the Agency can choose from among a broader set of 

ecological models, because the ecological models 

used need not directly link to existing information 

about economic benefits. As with monetized benefits, 

EPA can address the site-specificity of ecological 

impacts by using a bottom-up approach, and – if the 

relevant information about the joint distribution of the 

characteristics of ecosystems and human populations 

exists – aggregate the resulting estimates to the 

national level.

When monetization of benefits is not possible, the 

Agency should also seek to identify scientifically-based 

indicators of those benefits to the extent possible, i.e., 

it should seek to identify indicators in category 2. 
75

Some of the valuation methods discussed in chapter 4 

might be useful for this purpose. To the extent these 

methods generate biophysical and other measures that 

economic theory suggests are likely to be correlated 

with economic benefits, such measures can provide 

useful information about benefits when direct monetary 

estimates of those benefits are not available. For 

example, economic theory suggests that total economic 

benefits associated with an increase in wetlands in a 

specific area will depend, among other things, on the 

number of people who visit the area for recreational 

purposes. Other things being equal, the more people 

who visit the area, the higher the benefit associated 

with an increase in wetlands acreage. Likewise, the 

more people who live in the vicinity of an affected 

ecosystem, the greater the benefit associated with 

protecting that ecosystem. Similarly, if all other factors 

are equal, the more people who judge the protection of 

a given ecosystem service to be “somewhat important” 

or “very important” in a survey of attitudes and 

judgments, the higher the aggregate willingness-to-pay 

to protect that service is likely to be. Although these 

indicators do not typically reflect tradeoffs people are 

willing to make and hence would not provide monetary 

estimates of benefits that can be compared to cost, they 

can provide important information or signals about 

public preferences linked to possible benefits. 

Care must be taken to avoid misinterpreting these 

indicators. For example, just because a large population 

lives in the vicinity of an affected ecosystem does not 

necessarily mean that a change in that ecosystem has a 

large value. If the change relates to a service that is not 

important to people, the value of that change (e.g., the 

willingness to pay for it) would be low regardless of the 

number of people living in the vicinity. To draw correct 

inferences, EPA needs information not only about the 

number of people affected but also about the importance 

that individuals attach to the service, as revealed through 

surveys or other methods.

If ecological effects can be quantified but indicators 

of the associated benefits are not available (category 

3), EPA should report the effects in the most relevant 

biophysical units and discuss the basis for and expected 

direction of their link to possible benefits . For 

potentially important benefits for which quantification 

of the associated ecological changes is not possible 

(category 4 above), the Agency should characterize the 

changes as carefully as possible. It should discuss in 

detail why the changes are potentially important but 

not quantifiable, citing relevant literature. A carefully 

developed and scientifically based conceptual model 

can serve as the basis for a qualitative but detailed 

description of the ecological impacts of a given 

change. A simple summary of possible impacts is not 

sufficient. EPA should also provide justification based 

on the conceptual model and associated theoretical and 

empirical scientific literature. To the extent possible, 

the Agency should use the existing literature to draw 

inferences about the likely magnitude or importance of 

different effects, even if only qualitatively (e.g., high, 

medium, low). 

Although benefit-cost analysis requires the use of 

economic valuation to estimate benefits, regulatory impact 

assessments need not be limited to information generated 

for use in comparing benefits and costs. Information 

about other sources of value that are not fully captured 

by the theoretical framework underlying benefit-cost 

analysis (category 5 above) can still be of interest to 

policy makers when making decisions on ecological 

protection. For example, the spiritual or cultural value 

of some ecosystems and services may be an important 

consideration not adequately captured by direct measures 

or indicators of economic benefits. Several of the valuation 

methods described in chapter 4 can provide information 

about these other sources of value. 

An additional complexity, beyond the five categories 

for characterizing effects, arises from the national scale 

analysis required for most rule makings. Even when 

ecological models directly link to valuation, using 

these models to generate national-level estimates of the 

biophysical impacts of an EPA rule is very challenging, 

given the variability of ecosystem impacts within and 

across regions. The SAB has noted and discussed this 

point in other benefit assessment contexts, including 

the impact of Superfund sites (EPA Science Advisory 

Board, 2006c). To address variability across sites within 

a national assessment, the Agency should explore 

the use of a bottom-up approach to valuation. Under 

this approach, a number of case studies that reflect 

different types of ecosystems could be conducted. 

If information is available in a given rule making 

about the distribution of the ecosystem types and 

populations affected, EPA could aggregate these case 

studies to provide national-level estimates of changes 

in ecosystem services resulting from the rule. Even 

without full information about the distribution of 

ecosystem types and populations, the case studies could 

still provide information about the range of impacts and 

their dependence on ecosystem characteristics. This 

information could be useful not only for the specific 

policy decision at hand, but also in guiding future 

research. For example, it could suggest key ecosystem 

characteristics that would be useful in categorizing 

ecosystems for future valuation analyses and for which 

additional distribution information is needed. 

Once changes in ecosystem services are estimated, 

those changes must still be valued to generate national 

benefit estimates. The appropriate valuation approach 

will depend on the nature of the ecosystem services. 

For services that generate only local benefits, benefits 

transfer based on comparable previous studies of 

localized impacts can be used, provided the benefits 
76

transfer is conducted appropriately (see discussion in 

section 4.3). The local or regional benefit estimates 

can then be appropriately aggregated to the national 

level. However, for ecosystem services for which 

local impacts generate broader national benefits, 

use of localized studies for benefits transfer can be 

problematic, as noted above. For these services, 

benefits transfer should instead be based on studies 

that have generated value information at the national 

level, such as national surveys of willingness to pay for 

national-level changes in ecosystem services. However, 

few surveys of this type exist. To date, EPA has relied 

primarily on the national water quality survey of Carson 

and Mitchell (1993), which was conducted over 20 

years ago.49 Additional research is needed to generate 

estimates of economic benefits and other values that 

could appropriately be used for transfers of ecological 

values in national assessments.

In addition to its implication for how ecological 

valuations are conducted, the committee’s valuation 

approach also has implications for reporting value 

estimates in national benefit assessments. To increase 

transparency EPA should document in economic benefit 

assessments and RIAs the conceptual model used to 

guide the analysis and how decisions underlying the 

model were made. The assessments should describe how 

the ecosystem services were identified and the rationale 

for key choices regarding the focus of the assessment. 

Consistent with the guidance in Circular A-4, 

benefit assessments should also clearly identify the five 

categories of values outlined above. If methods other 

than economic valuation are used to provide quantitative 

or qualitative information about benefits, the RIA should 

include a discussion of the extent to which the methods 

provide indicators of willingness to pay or to accept. If 

non-economic methods are used to capture sources of 

value other than those typically reflected in willingness 

to pay, the RIA should describe the methods used.

When monetized economic benefits are aggregated, 

the resulting sum should always be described as “total 

economic benefits that could be monetized” rather than 

“total benefits.” In the past, EPA has sometimes reflected 

non-monetized benefits in aggregate measures of benefits 

by including an entry such as +X or +B in the summary 

table of benefits and costs to indicate the unknown 

monetary value that should be added to the benefits if 

the value could be determined. Although this approach 

indicates that the measure of monetary benefits 

is incomplete, the +X or +B designation provides 

insufficient information and can be easily overlooked in 

using the results of the benefit assessment. Designating 

the sum as “total economic benefits that could be 

monetized” provides a continual reminder of what is, 

and is not, included in this measure. EPA can provide 

a more accurate and complete indication of total 

benefits as called for by Circular A-4 by including key 

quantified but non-monetized impacts that are measured 

in biophysical units or in terms of expressed social 

importance or attitudes, if economic theory suggests 

those measurements are likely to be correlated with 

benefits, along with indicators of economic benefits and 

a detailed description of the non-quantifiable impacts. 

Because of the difficulties of estimating the 

biophysical impacts of an EPA rule and the associated 

values, the Agency must also characterize the 

uncertainty associated with its assessment. EPA 

should include a separate chapter on uncertainty 

characterization in each assessment. This chapter 

should discuss the scope of the assessment, the 

different sources of uncertainty (e.g., biophysical 

changes and their impacts; social information 

relevant to values; valuation methods, including 

transfer of willingness-to-pay or willingness-toaccept information), and the methods used to evaluate 

uncertainty. At a minimum, the chapter should report 

ranges of values and statistical information about the 

nature of uncertainty for which data exist. For each 

type of uncertainty, EPA should report information 

similar to that reported in the Agency’s prospective 

analysis of the benefits and costs of the Clean Air 

Act Amendments (EPA, 1999) and should provide a 

summary of this information in the executive summary 

of the assessment. Specifically, EPA should report 

potential sources of errors, the direction of potential 

bias for the overall monetary benefits and other value 

estimates and the likely significance relative to key 

uncertainties in the overall assessment. 

6.1.3.2 Research needs for improvements in 

future valuation

EPA can take the steps suggested above in the short 

run to improve ecological valuation, but additional 

improvements will require longer-term investments in 

research in at least three areas: national-level databases 

to support prediction of ecological impacts; means of 

mapping changes in stressors to changes in ecosystem 

services; and transfers of value-related information. 

Research is needed to develop national-level 

databases to predict ecological impacts (including 

baseline data on ecological conditions) and to value 

those impacts (including data on affected human 

populations). The current availability of national-level 

databases with this information is limited. In addition, 

research is needed on the joint distribution of relevant 

ecosystem and human population characteristics across 

local or regional sites that can be used to aggregate 

case studies in a bottom-up approach to national-level 

assessments. As noted above, case studies provide a 

means of incorporating heterogeneity regarding both 

ecological impacts and values. However, to generate 

national-level estimates for use in national rule 

making, results from case studies must be aggregated 

using weights that reflect the distributions of the 
77

relevant combinations of biophysical and population 

characteristics. Research to identify both the key relevant 

characteristics and their joint distributions is needed.

As discussed in chapter 3, research is needed to 

develop ecological production functions and associated 

models that can map changes in stressors to changes 

in ecosystem services. In the past, EPA has often 

been unable to estimate certain values because the 

Agency was not able to predict how a given rule 

would change stressors and how those changes would 

in turn affect ecosystem services. Both baseline data 

and the development of ecological models that focus 

on ecosystem services, as well as other ecosystem 

characteristics of importance to people, are needed. 

The datasets and models should support aggregate, 

national-level assessments.

Finally, additional research related to benefits transfer 

and transfers of other value-relevant information is 

needed, including both research on methodological 

issues that arise in transferring values across different 

contexts, as well as additional original valuation 

studies that the Agency can use for this purpose. These 

new studies should focus on value estimates that can 

be applied in multiple contexts (e.g., recurring rule 

makings) and across a broader geographical scale. 

Loomis and Rosenberger (2006) suggest features of 

study design that facilitate the use of a study’s results 

in benefits transfer. These include use of objective 

quantitative measures of quality: measured in policyrelevant physical units; the evaluation of realistically 

small changes; the provision of information about 

relevant baselines; and the full and consistent reporting 

of results. New studies should also expand the range 

of ecosystem services valued so that transfers can be 

applied to a wider range of services and/or ecological 

impacts. 

In addition to localized studies that could be used 

as study sites, national-level studies are also needed for 

ecological valuation in national rule making. National 

economic valuation surveys (such as the one conducted 

by Carson and Mitchell [1993]) that have recent data and 

a specific focus on ecosystem services have the potential 

to contribute significantly to the Agency’s ability to 

conduct ecological benefit assessments to support national 

rule making, provided they are conducted in accordance 

with state-of-the-art survey procedures (see SAB Web 

site at http://yosemite.epa.gov/Sab/Sabproduct.nsf/

WebFiles/SurveyMethods/$File/Survey_methods.pdf for 

detailed information about the use of survey methods for 

ecological valuation.). Because conducting surveys for 

individual rule makings is prohibitively costly in both time 

and resources, the Agency should focus on conducting 

a limited number of surveys designed to provide value 

information usable in multiple rule makings. 

Toward this end, the Agency should develop 

a research program (both internally and through 

extramural grants) focused on developing methods and 

value estimates specifically for use in recurring rule 

makings (e.g., for rule making associated with National 

Ambient Air Quality Standards or Effluent Guidelines). 

In past years, EPA has targeted some of its Science To 

Achieve Results (STAR) grant resources toward benefits 

transfer, but a larger and more concerted effort focused 

on ecological valuation and the use of transfers in 

national rule making is clearly needed. 

6.1.4 Summary of recommendations 

To develop more comprehensive estimates of the 

value of ecological changes associated with national 

rules and regulations, the Agency needs a broader 

approach to ecological valuation than it has typically 

used in the past. The expanded approach to valuation 

proposed in this report can and should be applied to 

national rule making. This would entail challenges, 

but important opportunities for improvement as 

well. EPA can implement some of the committee’s 

recommendations using the existing knowledge base. 

Other recommendations call for research to enhance 

the Agency’s future capacity to conduct high-quality, 

scientifically-based ecological valuation for national 

rule making.

The Agency can improve ecological valuation for 

national rule making in the short run by incorporating 

the following recommendations:

o The Agency should begin each valuation exercise 

with the development of a conceptual model of the 

ecological system being analyzed and the ecosystem 

services that it generates. This model should serve as 

a guide or road map for the assessment. 

o EPA should develop the model using input about 

both the relevant science and public preferences and 

concerns to ensure that it incorporates important 

ecological functions and processes as well as related 

ecosystem characteristics and services that are 

potentially important to people. Public concerns can 

be identified through a variety of methods, drawing 

on either existing knowledge or an interactive process 

to elicit public input.

o Once the Agency has identified a list of potentially 

important ecological effects and associated services, it 

should categorize those effects according to the extent 

to which they can be quantified and monetized at the 

national level using economic valuation techniques 

including benefits transfer. 

o To address site-specific variability in the impact of 

a rule, the Agency’s assessments should include 

case studies for important ecosystem types. 

Aggregation across these case studies can be carried 

out if information about the joint distribution of 
78

ecosystem types and characteristics of affected human 

populations is available. This bottom-up approach 

would establish separate estimates for each locality or 

region and then aggregate them to obtain a national 

estimate. 

o For ecosystem services for which the benefits are 

primarily local, EPA can rely on scientifically-sound 

benefits transfer using prior valuations at the local 

level. However, for services valued more broadly, 

the Agency should draw from studies with broad 

geographical coverage (in terms of both the changes 

that are valued and the population whose values are 

assessed). 

o EPA should report aggregated monetized economic 

benefits as “total economic benefits that could be 

monetized” rather than “total benefits” ) (category 1 

on page 74)

o To assess the benefits associated with effects that 

cannot be monetized for national rule making using 

scientifically sound valuation methods (including 

benefits transfer), EPA should:

	 • provide a scientific basis for the importance of any

projected ecological changes, whether they are 

monetized or not

	 • include characterization of potentially important

effects related to categories 2, 3, and 4 discussed on 

page 74:

 Category 2: Effects for which benefits cannot 

be monetized, but that can be quantified in 

biophysical terms using available ecological 

models and for which some indicator(s) of 

economic benefits exist.

 Category 3: Effects that can be quantified in 

biophysicial terms but for which no indicators of 

economic benefits exist.

 Category 4: Effects that can be qualitatively 

described and generally related to benefits based 

on available ecological and social science, even if 

they cannot be quantified.

o EPA should also consider assessing values associated 

with effects that are likely to generate important noneconomic values (based, for example, on moral or 

spiritual convictions) (category 5 on page 74). Even 

though these values do not properly fit within a formal 

economic benefit-cost analysis, they can provide 

important additional information to support decision 

making. When such value estimates are included in 

RIAs, the RIA should discuss both the valuation method 

and the results in a separate section. 

o EPA should include a separate chapter on uncertainty 

characterization in each assessment. 

To enhance the Agency’s capacity to conduct future 

ecological valuations, EPA should support research 

specifically designed to facilitate ecological valuation 

for national rule making, particularly for recurring rule 

makings. The committee recommends that EPA focus on 

at least three areas of research: 

o EPA should support the development of national level 

databases to support valuation, including data on the 

joint distribution of ecosystem and human population 

characteristics that are important determinants of the 

value of ecological changes. 

o EPA should support the development of quantitative 

ecosystem models and baseline data on ecological 

stressors and ecosystem service flows that can support 

national-level predictions of the consequences of 

changes in ecological stressors on the production of 

ecosystem services.

o EPA should support the development of additional 

methodological and original valuation studies 

designed to enhance national-level ecological values 

transfer, including national surveys relating to 

ecosystem services with broad (rather than localized) 

effects that can generate value estimates for use in 

multiple rule making contexts. 

6.2 Valuation in regional partnerships

6.2.1 EPA’s role in regional-scale 

value assessment 

Significant opportunities exist to use regional-scale 

valuations of ecosystem services to guide decision 

making by EPA and sub-national governments to protect 

and restore the environment. Many important ecological 

processes take place at a landscape scale. For example, 

habitat connectivity on landscapes, water and nutrient 

flows through watersheds, and patterns of exposure and 

deposition from air pollution in an airshed pose issues 

larger than a particular site and thus require regionalscale analysis. 

An increase in data and methods, supported by EPA 

research, has also opened new frontiers for regionalscale analysis of ecosystems and their services. Publicly 

available, spatially explicit data on environmental, 

economic, and social variables have increased 

dramatically in recent years. At the same time, the ability 

to display data visually in maps and to analyze spatially 

explicit data using a variety of analytical models and 

statistical methods has expanded. An active EPA 

program in ecological research is underway for regionalscale analysis of ecosystems and services. As part of that 

program, EPA has funded research relating to restoration 

of water infiltration in urbanizing watersheds in 

Madison, Wisconsin, restoration of multiple ecosystem 

functions for the Willamette River in Oregon, decisionsupport tools to meet human and ecological needs in 

New England rivers, and the provision of multiple 

services from agricultural landscapes in the upper 

Midwest. As discussed in section 6.2.3.2, EPA Region 
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4: Southeast has developed a tool for regional ecological 

assessment. Other regions have also undertaken 

assessments of ecosystem services.

There is great potential – largely untapped to date – to 

use this type of analysis to aid regional decision making. 

Municipal, county, regional, and state governments make 

many important decisions affecting ecosystems and the 

provision of ecosystem services. Examples include landuse planning and watershed management. Unfortunately, 

local and state governments rarely have the technical 

capacity or the necessary resources to undertake 

regional-scale analyses of the value of ecosystems or 

their services or to incorporate these values into their 

decision making processes. 

Regional partnerships among EPA, other governmental agencies, and the private sector offer the 

potential for expanding national, state, and local 

capacity to value and protect ecosystems and their 

services. EPA regional offices have many opportunities 

to collaborate at a regional scale with local and state 

governments, regional offices of other federal agencies, 

non-governmental environmental organizations, and 

private industry. Through collaborating with such 

groups, EPA can enhance environmental protection 

by engaging the public, gaining access to regional 

expertise, and promoting effective decision making 

on important regional-scale environmental decisions. 

Local and state partners can gain from access to EPA 

technical expertise and resources. Such partnerships 

can expand the knowledge base for decision making 

and improve the analysis of the value of ecosystems 

and services. 

Unlike national rule making, where specific statutes 

or regulatory mandates often constrain analysis, regions 

have more freedom to use novel approaches to valuing 

ecosystems and their services. Such use, even on a pilot 

basis, may lead to improved methods and practices of 

valuation with potential positive impacts well beyond the 

region that pioneers the innovations. For example, EPA 

can use regional-level partnerships as a mechanism for 

testing and improving various valuation methods that 

might ultimately be used at the national level. 

Because of the absence of legal or statutory 

requirements that EPA value ecosystems or services 

at the regional scale, there have been few regional 

ecological valuation efforts to date. In addition, 

regional offices may have lacked the time, resources, 

and expertise to undertake some of the crucial steps 

recommended in this report for valuing ecosystems 

and their services. For example, few regional offices 

have economists or other social or behavioral scientists 

on staff who can work on valuations. Partly for these 

reasons, many of the potential advantages of regional 

partnerships for valuing ecosystems or their services 

have not been realized to date. 

To analyze opportunities for regional partnerships 

for valuation, the committee, through the SAB Staff 

Office, surveyed regional offices for examples of 

where the Agency or other governmental agencies have 

engaged in regional valuation efforts (EPA Science 

Advisory Board Staff, 2004). This section explores 

three case studies from Chicago; Portland, Oregon; and 

the Southeast. The case studies illustrate several general 

lessons about regional-scale analysis of the value of 

ecosystems and services and the potential usefulness of 

regional partnerships.

6.2.2 Case study: Chicago Wilderness

Chicago Wilderness is an alliance of more than 

180 public and private organizations. The overall goal 

of Chicago Wilderness, as stated in its Biodiversity 

Recovery Plan, is “to protect the natural communities 

of the Chicago region and to restore them to longterm viability, in order to enrich the quality of life of 

its citizens and to contribute to the preservation of 

global biodiversity” (Chicago Wilderness, 1999, p. 7). 

Chicago Wilderness is a bottom-up organization. No 

single decision maker or agency controls or guides 

Chicago Wilderness. It pursues objectives, as defined by 

its members, through consensus. Chicago Wilderness 

pursues its goals and objectives by promoting a green 

infrastructure to support biodiversity and to maintain 

ecosystems and services linked to quality of life in the 

Chicago metropolitan area. 

As a member of Chicago Wilderness, EPA Region 5 

(serving Illinois, Indiana, Michigan, Minnesota, Ohio, 

Wisconsin, and 35 Tribes) has provided technical and 

financial assistance and facilitates the partnership. EPA 

expertise in Region 5, particularly in natural sciences, 

has contributed to quantifying ecosystem services and 

understanding how potential stressors affect ecosystems 

and the provision of services. Chicago Wilderness 

has produced several reports, as well as a Biodiversity 

Recovery Plan and a green infrastructure map for the 

region.50 The Chicago Wilderness Web site (http://www.

chicagowilderness.org/) contains a chronology and links 

to many relevant documents, including the Biodiversity 

Recovery Plan.

Chicago Wilderness has been interested in valuing 

ecosystems and services, but has only begun to explore 

the opportunities. Although no specific legal authority 

mandates valuation of ecosystems or services as part 

of the work of Chicago Wilderness, quantifying values 

associated with the conservation of green space and 

biodiversity could help Chicago Wilderness meet its 

own stated objectives and communicate its analysis to 

other groups and the general public. The possible uses 

of valuation identified by Chicago Wilderness members 

include: 

o Informing decisions on the establishment of green 

infrastructure, including priorities for acquisition of 
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land by, for example, forest preserve districts or soil 

conservation districts 

o Assessing the value of preserving ground water and 

ecosystem services related to clean water 

o Assessing the relative value of conventional versus 

alternative development and demonstrating conditions 

in which development decisions that have positive 

impacts on the environment might be in the financial 

interest of the developer 

o Communicating effectively with residents of 

the Chicago region regarding the value of green 

infrastructure and biodiversity and how these relate to 

residents’ quality of life

o Assessing the relative value of investing in different 

research projects to establish priorities for funding 

decisions

Members of Chicago Wilderness, however, possess 

only limited technical expertise and practical experience 

in valuing the protection of ecological systems and 

services. EPA Region 5 also has limited capacity to value 

ecosystem services. 

In sum, Chicago Wilderness, like many regional 

partnerships, would gain much from the ability to 

analyze the value of ecosystems and services, but it is 

constrained by lack of expertise and resources. 

6.2.2.1 An example of how valuation could 

support regional decision making

Valuation of ecosystems and services is most 

useful when done in the context of specific decisions 

affecting the environment. The committee therefore 

chose a specific decision context – county open 

space referenda in the Chicago metropolitan area – to 

explore how this report’s approach to valuation could 

support regional decisions. 

Voters in four counties in northeastern Illinois have 

passed referenda authorizing bonds to purchase land 

for open space preservation or watershed protection. In 

November 1997, voters in DuPage County passed a $70 

million open space bond. In November 1999, voters in 

Kane County and Will County passed bond issues totaling 

$70 million for open space acquisition or improvement. 

In 2001, the voters in McHenry County passed a $68.5 

million bond for watershed protection. Although these 

multi-million dollar bond proposals have provided 

substantial funding to preserve open space and ecological 

processes in the region, the funds are insufficient to 

protect all worthwhile open space and watersheds. Given 

this shortfall, input about the most important lands to 

purchase or management actions to undertake to maintain 

or restore natural communities would help ensure that 

counties invest these funds wisely. 

This section of the report looks at how valuation 

could help inform conservation investments under the 

local county bonds. The section examines three sources 

of values derived from protecting natural systems: 

o Conservation of species and ecological systems

o Water quality and quantity

o Recreation and amenities

The discussion of water quality and quantity focuses 

on McHenry County because the bond issue there related 

directly to watershed protection. Following the process 

outlined in chapter 2 of this report, the section explores: 

the role of public involvement and input in determining 

ecosystem services of interest, predicting ecological 

impacts in terms of effects on these ecosystem services, 

and assessing and characterizing the values of these 

effects on the ecosystem services. 

6.2.2.2 Public involvement, scientific and 

technical input, and public participation

The planning documents and activities of Chicago 

Wilderness illustrate several of the themes from chapter 

2 of this report, including broad public involvement and 

interdisciplinary collaboration. Chicago Wilderness has 

made extensive efforts to engage the local community 

in determining the most important features of regional 

ecosystems and services. Two of the strengths of the 

organization are the broad range of groups involved and 

its commitment to open processes. Chicago Wilderness 

participants themselves define the objectives, goals, and 

priorities of the organization. As a result of the open, 

democratic process and the efforts to include multiple 

views and voices, the group’s goals and objectives 

largely reflect what people in the region view as 

important to conserve. Engaging local communities is 

a vital first step in the process of valuing ecosystems 

and services. Engagement helps to focus scarce agency 

resources on issues of prime local importance, as well as 

to promote partnership and dialogue. 

The inclusive planning process followed by Chicago 

Wilderness has included developing a common 

statement of purpose, setting up three working groups 

(steering, technical, and advisory committees), and 

working through nine planning steps (from visioning, 

development of inventories, assessment of alternative 

actions, to adopting a plan). In its early stages, Chicago 

Wilderness conducted workshops and meetings to 

define implementation strategies and to prioritize 

among its long- and short-term goals, which focus on 

the restoration and conservation of biodiversity. For 

priority setting, several of the workshops used valuation 

exercises to derive qualitative rankings of importance. 

Chicago Wilderness also referenced other valuation 

measures, such as polls and The Nature Conservancy’s 

global rarity index.51

Chicago Wilderness conducted eight workshops 

to assess status and conservation needs for natural 

communities in the area: four workshops on species, 
81

addressing birds, mammals, reptiles, amphibians, and 

invertebrates; and four consensus-building workshops on 

natural communities, addressing forests, savanna, prairie, 

and wetlands. The natural-communities workshops 

developed overall relative rankings based on the amount 

of area remaining, the amount protected, and the quality 

of remaining areas (incorporating fragmentation and 

current management). The workshops assessed relative 

biological importance for community types, based on 

“species richness, numbers of endangered and threatened 

species, levels of species conservation, and presence 

of important ecological functions (such as the role of 

wetlands in improving water quality in adjacent open 

waters)” (Biodiversity Recovery Plan, chapter 4, p. 41). 

The workshops identified visions of what the areas 

should look like in 50 years. 

Two different groups of scientists and land 

managers developed a classification scheme for 

aquatic communities based on physical characteristics. 

The groups assigned recovery goals (i.e., protection, 

restoration, rehabilitation, and enhancement) to 

streams and priority levels (i.e., exceptional, important, 

restorable, and other, based on Garrison, 1994-95) to 

lakes. The groups assessed streams using the index 

of biotic integrity, species or features of concern, the 

macroinvertebrate biotic index, and abiotic indicators. 

The groups also assessed threats and stressors to streams, 

lakes, and near-shore waters of Lake Michigan. 

One disadvantage of Chicago Wilderness’ broad 

engagement of local communities is the time-consuming 

nature of community involvement processes. The 

organization is not well placed to make rapid analyses 

or provide feedback on decisions that occur over a short 

time period. 

6.2.2.3 Predicting ecological impacts in terms of 

changes in ecosystem services 

Because Chicago Wilderness is committed to the 

value of protecting biodiversity, it is interested in 

predicting impacts on the conservation of species 

and ecological systems at the landscape scale. It has 

collected spatially explicit information relevant to land 

use, open space, recreation, biodiversity conservation, 

water quality, and water quantity. It has also 

successfully applied a variant of the conservation value 

method to identify and prioritize conservation actions 

through spatial representation and analysis of unique 

and threatened species and ecosystems. Use of the 

method demonstrates how conservation science can be 

used for planning, and how a transparent approach to 

mapping conservation goals can be useful in a regional 

partnership.

However, for this spatially-explicit information to 

be relevant to decisions affecting ecosystems, Chicago 

Wilderness needs cause-and-effect relationships that 

can predict how policy choices will affect ecosystems 

and services. It does not have the information to 

estimate ecological production functions. Although it 

can be effective in providing descriptive information 

– particularly in the form of maps – it is limited in 

its ability to analyze alternative policies and make 

recommendations about which alternatives are 

preferable. For example, Chicago Wilderness would 

be able to provide only limited guidance to a decision 

maker in McHenry County concerning how to invest 

the $68.5 million approved by voters for watershed 

protection in a way that would maximize the value of 

ecosystems and services, because it would not be able to 

martial information about how particular actions affect 

systems and services.

Possible ecological impacts and provision of 

services from the protection or restoration of 

watersheds 

Watersheds figure prominently in Chicago Wilderness’ 

work. The protection or restoration of watersheds 

can have a number of impacts on ecosystem services, 

including water quality, water quantity, and the support 

of ecological communities.

Surface water

o Availability – More water will be retained in 

the watershed because there is less runoff from 

impervious surfaces.

o Periodicity of flows – Changes in the hydrograph are 

mitigated because precipitation will be captured in the 

soil and vegetation, and subsequently released more 

slowly.

o Maintenance of minimum flows – There is a greater 

chance of maintaining adequate minimum flows 

because of the dampening effects of intact watersheds 

and continuation of subsurface flows.

o Flooding – Flooding is reduced because of the 

retention capabilities of the intact watershed.

Subsurface water

o Availability for domestic and industrial use – 

Availability will be increased because percolation and 

subsurface recharge will be enhanced by natural soil 

surface and vegetation.

o Maintenance of wetlands – Those habitats that 

depend on the water table or subsurface flow will be 

enhanced because natural percolation and recharge 

processes will be maintained.

Water quality

o Pollution dilution – Increased flows will dilute 

concentrations of organic and inorganic pollutants.

o Assimilation of biotic pollutants – Increased 

stream flows will permit greater opportunity for the 

assimilation of biological materials.

o Biological communities – Habitats that depend on 

increased quantities of water in the watershed and 
82

containing protected species will enjoy increased 

persistence.

o Specific habitats – Increased water quantity and 

more uniform stream flows will support regionally 

important ecological communities, e.g., in-stream 

communities, bottomland forests, wetlands, and wet 

prairies.

For illustrative purposes, suppose Chicago 

Wilderness wished to characterize impacts in McHenry 

County on three ecosystem services: minimizing 

flooding, maintaining or increasing groundwater 

recharge, and maintaining or increasing wetland 

communities. To predict impacts related to flooding, 

Chicago Wilderness could make use of a geographic 

information system (GIS) database it developed that 

includes layers depicting rivers, streams, wetlands, 

forest lands, and floodplains. As a first approximation, 

Chicago Wilderness could use historical records of 

flooding in McHenry County watersheds to identify 

watersheds with the greatest potential for flooding. 

It could then evaluate the potential for restoring 

floodplain forests and wetlands for mitigating flooding. 

To estimate whether a development option would 

adequately maintain or increase groundwater resources, 

it could use the maps of aquifers and soils in the GIS 

database that describe run-off and percolation rates for 

each soil type. Watersheds could be compared in terms 

of potential for aquifer recharge. Chicago Wilderness 

could then consider the effects of alternative land use 

decisions on recharge (Arnold and Friedel, 2000). 

To address whether wetland communities would be 

maintained or increased, topographic maps and GIS 

data on rivers, streams, floodplains, forests, wetlands, 

and land cover could be used to rank watersheds within 

McHenry County in terms of potential wetlands minus 

current wetlands. The potential for expanding existing 

wetlands or restoring wetlands within watersheds could 

then be measured.

A number of GIS data files for McHenry County 

thus could assist in understanding how the protection 

of a given part of a watershed contributes to ecosystem 

processes and services. What is often lacking, however, 

is a cause and effect relationship that could be used to 

predict how alterations in management or policy would 

change the provision of ecosystem services. It might be 

possible to transfer results from studies of ecological 

services from other regions. For example, Guo et al. 

(2000) measured the water flow regulation provided by 

various forest habitats in a Chinese watershed. If these 

relationships are transferable, estimates of the effect of 

a policy of restoring forest habitat on water flow could 

be generated. Changes in water flow could then be 

used to predict impacts on aquatic organisms and their 

production functions such as waterfowl, fisheries, and 

wildlife viewing (Kremen, 2005).

In trying to predict how policy choices will affect 

ecosystems and the provision of services, experts must 

be careful not to substitute their own values for those of 

the public. Different judgments used in models may give 

rise to different recommendations. 

6.2.2.4 Valuation of changes in ecosystems and 

services

Government decisions about what lands to conserve 

can involve tradeoffs among different ecosystem services 

of importance to the public. A study conducted in the 

Chicago metropolitan area, for example, found a tradeoff 

between desires to locate open space access close to 

people’s homes and desires to locate open space to 

conserve species (Ruliffson et al., 2003). When there 

are such tradeoffs among different services, decision 

makers need information about the value of various 

aspects of ecosystems and services in order to determine 

what alternatives are more beneficial for the community. 

This information about relative values goes beyond 

understanding the ecological impacts of the management 

and policy alternatives and also reflects people’s 

concerns and desires. 

This section begins with a discussion of the potential 

contributions that valuation could make to Chicago 

Wilderness and briefly examines possible valuation 

methods that could be applied for different types of 

ecosystem services. This discussion goes well beyond 

what Chicago Wilderness has actually done in the 

valuation realm. The organization has conducted very 

few quantitative valuation studies and largely lacks the 

resources and the expertise to do so. 

In one sense, however, Chicago Wilderness 

carried out an important valuation exercise at its very 

outset when it engaged its member organizations 

and gathered feedback on what the community felt 

was important. This process resulted in an important 

statement about the values held by the collection of 

organizations that constitute Chicago Wilderness. As 

noted earlier, its overall goal is “to protect the natural 

communities of the Chicago region and to restore them 

to long-term viability, in order to enrich the quality of 

life of its citizens and to contribute to the preservation 

of global biodiversity.” 

Given this clear goal statement, formal valuation 

studies that try to value the benefits of alternatives 

in monetary terms may be of secondary importance. 

Of primary importance is to understand how various 

potential strategies contribute to the protection and 

restoration of natural communities and the ecosystem 

services they provide. As noted earlier, Chicago 

Wilderness has used a variant of the conservation 

value method to identify and prioritize conservation 

actions that would contribute to this goal through 

spatial representation and analysis of biodiversity 

and conservation values. Not surprisingly, Chicago 
83

Wilderness has devoted most of its attention to 

biophysical measures of the status of natural 

communities. It has devoted much less attention to 

quantitative measures of value, monetary or otherwise. 

With a clearly stated overall goal “to protect the 

natural communities of the Chicago region and to 

restore them to long-term viability,” economic analysis 

may be largely restricted to estimating the cost of 

various potential strategies to achieve that objective. 

Cost-effectiveness analysis addresses how best to 

pursue a specific objective, given a budget constraint. 

Information about how potential strategies contribute to 

the protection and restoration of natural communities 

and about the cost of these strategies is the main 

information needed. There is no need to estimate 

the value of protecting natural communities or other 

ecosystem services. 

Of course, things are rarely so clear. Even with a single 

overall goal, there are often multiple dimensions and 

tradeoffs among those dimensions that require an analyst 

to go beyond cost-effectiveness analysis. For example, in 

protecting natural communities, there may be tradeoffs 

between protecting one type of natural community versus 

another. When there are multiple natural communities 

or ecosystem services of interest, it becomes important 

to address questions of value – a practical matter 

when investment of bond monies is at stake. Is it more 

valuable to allocate resources to restoring upland forest 

or wetlands? Is it more valuable to mitigate flood risk or 

improve water quality? Such questions can be addressed 

only by comparing the relative value attached to different 

natural communities or services. 

Economic valuation of the protection of natural 

communities may be important for Chicago Wilderness 

and the public at large for several reasons. First, 

when there are multiple sources of value generated 

by protecting natural communities (e.g., species 

conservation, water quality, flood control, recreational 

opportunities, aesthetics, etc.), monetary valuation 

provides a way to establish the relative importance of 

various sources of value. With prices or values attached 

to different ecosystem services, one can compare 

alternatives based on the overall economic value 

generated. Second, some biological concepts such as 

biodiversity are multi-faceted. How one makes tradeoffs 

among different facets of biodiversity conservation or 

among different natural community types is ultimately 

the same question as how one makes tradeoffs among 

multiple objectives. Establishing prices on different 

components of biodiversity or on different natural 

communities allows for analysis of tradeoffs among 

components and an assessment of the overall value of 

alternatives. Finally, monetary valuation may facilitate 

communication about the importance of protecting 

and restoring natural communities in terms readily 

understood by the public.

Non-monetary valuation can also be useful. If 

decisions involve tradeoffs among different natural 

communities or services, surveys containing attitude 

questions may be helpful. In some cases, people may 

find it easier to say whether they think it more important 

to provide additional protection of forests versus 

wetlands than to state the monetary value of protecting 

forests rather than wetlands.

People may value natural communities because of 

the ecosystem services they provide or because of their 

existence or intrinsic values. Of these two sources of 

value, the ecosystem services are generally the easier 

to value. Consider how Chicago Wilderness might 

value protecting wetlands and other watershed lands for 

flood control and water quality. To measure the value 

of flood control, it might measure avoided damages. 

Several studies of the value of preserving wetlands for 

flood control have been undertaken in Illinois, including 

studies of the Salt Creek Greenway (Illinois Department 

of Conservation, 1993; USACE, 1978) and the value 

of regional floodwater storage from forest preserves in 

Cook County (Forest Preserve District of Cook County, 

Illinois, 1988). The Cook County study found estimated 

flood control benefits of $52,340 per acre from forest 

preserves. The value of providing clean drinking water 

to the public is extremely high, far exceeding the costs 

of supplying it either by natural or human-engineered 

means. Because the question is how, not whether, to 

supply clean drinking water, replacement cost (e.g., the 

cost of building a filtration system to replace lost water 

purification services provided by wetlands) can be used 

to value the contribution of ecosystems to the provision 

of clean drinking water. 

A large literature in environmental economics 

exists on estimating the values of various recreational 

opportunities and environmental amenities created by 

the natural environment. As discussed below, typical 

methods used to estimate the monetary value of 

recreation and environmental amenities include hedonic 

property price analysis, travel cost, and stated preference. 

A smaller literature uses referenda voting to infer values 

for open space and other environmental amenities. 

Hedonic property price analysis is a common method 

for estimating the value of environmental amenities, 

especially in urban areas because of the availability of 

large data sets on the value of residential property values. 

Analysts have used the hedonic property price model 

to estimate the value of air quality improvements (e.g., 

Ridker and Henning, 1967; Smith and Huang, 1995), 

living close to urban parks (e.g., Kitchen and Hendon, 

1967; Weicher and Zeibst, 1973; Hammer et al., 1974), 

urban wetlands (Doss and Taff, 1996; Mahan et al., 2000), 

water resources (e.g., Leggett and Bockstael, 2000), urban 

forests (e.g., Tyrvainen and Miettinen, 2000), and general 

environmental amenities (e.g., Smith, 1978; Palmquist, 

1992). Although Chicago Wilderness has not used this 
84

method to date, the large number of residential property 

sales in the Chicago area and spatially explicit databases 

on many environmental attributes offers great potential to 

use hedonic property price analysis to estimate the values 

of environmental amenities. 

A large literature has used the travel cost method to 

value recreation sites. With the large number of visitors 

to Lake Michigan beaches, forest preserves, and parks 

in the Chicago metropolitan area, Chicago Wilderness 

could also apply travel cost to estimate the value of 

recreational activities. Several studies have applied 

the travel cost method in urban areas (e.g., Binkley 

and Hannemann, 1978; Lockwood and Tracy, 1995; 

Fleischer and Tsur, 2003). 

Stated-preference methods can also be used to 

estimate the value of recreational opportunities and 

environmental amenities. In one such study completed 

for Chicago Wilderness, Kosobud (1998) used a 

contingent valuation survey to estimate willingness to 

pay for the recovery or improvement of natural areas 

in the Chicago region. Kosobud found an average 

willingness to pay for expanded natural areas of 

approximately $20 per household per year. Extrapolating 

over the number of households in the region, expansion 

of natural areas in the region would generate about $50 

million per year in benefits.

Finally, there is a small but growing literature that 

estimates values from voting behavior in referenda 

involving environmental issues. In particular, studies 

have analyzed the value of open space using results of 

voting on open-space referenda (Kline and Wichelns, 

1994; Romero and Liserio, 2002; Vossler et al., 2003; 

Vossler and Kerkvliet, 2003; Schläpfer and Hanley, 2003; 

Schläpfer et al., 2004; Howell-Moroney, 2004a, 2004b; 

Solecki et al., 2004; Kotchen and Powers, 2006; Nelson et 

al., 2007). As noted earlier, several counties in the Chicago 

metropolitan area have passed referenda authorizing 

bonds to purchase open space or protect watersheds. 

Although the number of referenda is relatively small, 

making it difficult to generalize or make comprehensive 

statements about values, analysis of these referenda could 

provide insights into the values different segments of the 

public place on various environmental amenities.

The only methods currently accepted by economists 

for estimating non-use values, such as the existence 

value of natural communities or biodiversity, are statedpreference methods such as contingent valuation and 

conjoint analysis. To estimate the existence value of 

protecting species and ecological systems, Chicago 

Wilderness could survey respondents in the Chicago 

area. Alternatively, it could attempt to use economic 

benefits transfer by applying the results of relevant 

surveys done in other locations. The advantage of 

obtaining a monetary value for the conservation of 

species and ecological systems through contingent 

valuation or conjoint analysis is that it would allow 

Chicago Wilderness to calculate a total economic value 

for alternative strategies. Without contingent valuation or 

conjoint analysis, non-use value could not be included, 

and only a partial economic value estimate for each 

strategy could be derived. 

Any effort to estimate a monetary non-use value 

raises the question of whether monetary values fully 

reflect the values held by Chicago residents related to 

the protection of natural communities. In discussing 

the importance of protecting biodiversity, Chicago 

Wilderness emphasizes that a survey of Chicago focus 

groups found that “responsibility to future generations 

and a belief that nature is God’s creation were the two 

most common reasons people cited for caring about 

conservation of biodiversity” (Biodiversity Recovery 

Plan, p. 14). Contingent valuation of the bequest value 

of biodiversity might be consistent with measuring 

responsibility to future generations, although the 

respondents in the focus group were presumably 

thinking in moral rather than monetary terms. Strong 

differences of opinion exist on whether it is appropriate 

to try to capture such notions as stewardship or moral 

values in monetary terms using stated preference 

methods (Sunstein et al., 2002; Sen, 1977).

Citizen juries or decision-science methods also 

provide a useful means of evaluating tradeoffs among 

potential strategies in the Chicago Wilderness context. 

With citizen juries, experts could work with a small 

group of selected individuals in the Chicago area to 

determine comparative values for parcels of land through 

a guided process of reasoned discourse. These methods 

might enable participants to develop more thoughtful 

and informed valuations, better analyze tradeoffs among 

multiple factors, and engage in a more public-based 

consideration of values. Decision science methods could 

provide either monetary comparisons of the values of 

alternative properties or weights that could be used to 

aggregate multiple layers of data.

Monetary values derived through citizen juries or 

decision science approaches may differ considerably 

from traditional economic measures based on individual 

welfare, for various reasons. Monetary values derived 

through citizen juries, for example, may differ both 

because of the consent-based choice rules employed and 

the explicitly public-regarded nature of the valuation 

exercise. Recent analysis suggests that deliberative 

valuations, in which a small, select group of individuals 

explores the values that should guide collective decisions 

through a process of reasoned discourse, may aggregate 

individual values in a manner that systematically departs 

from the additive aggregation procedures of standard 

benefit-cost analysis (Howarth and Wilson, 2006). 

Although valuation information could be of great use 

to decision makers in evaluating alternative strategies 
85

and in communicating consequences of the alternatives 

to the public, Chicago Wilderness has undertaken very 

little valuation research or analysis. Despite some 

attempts to collect information about the value of 

protecting natural communities and ecosystem services 

(e.g., Kosobud, 1998), Chicago Wilderness’ efforts have 

not been comprehensive or systematic. This contrasts 

with its major efforts to garner broad public involvement 

and input in setting the goals for the organization and 

its large-scale effort to collect technical and scientific 

knowledge to characterize the status of ecosystems and 

species. In part, the lack of valuation activity has been 

the result of the mix of expertise of the individuals 

involved in Chicago Wilderness. In part, the lack of 

valuation activity is the result of the organization’s 

choice regarding the set of activities most important 

to it (which is a different sort of revealed preference). 

Chicago Wilderness is interested in using economic and 

other social-science approaches to study the value of 

protecting natural communities but has not yet enjoyed 

the right mix of expertise and circumstances to make this 

a reality. 

6.2.3 Other case studies

6.2.3.1 Portland, Oregon’s assessment of the 

value of improved watershed management

In the early 2000s, Portland, Oregon, decided to 

analyze the ecosystem benefits and ecosystem-service 

values that would result from improved watershed 

management. Portland officials hoped to find more 

effective approaches to watershed management that 

could both save the city money and improve the 

well-being of its citizens. The city was particularly 

interested in impacts on flood abatement, water quality, 

aquatic species (salmon in particular), human health, 

air quality, and recreation. The city’s Watershed 

Management Program requested David Evans and 

Associates and ECONorthwest to undertake the study, 

completed in June 2004 (David Evans and Associates 

and ECONorthwest, 2004). Although not an example 

of a regional partnership with EPA, the project provides 

one of the best examples of the kind of landscapescale analysis of the value of ecosystems and services 

recommended by this report. 

City officials realized that they understood only 

a portion of the contributions to well-being from 

improved watershed management. To be able to 

make more intelligent decisions about watershed 

management, these officials wished to have a more 

complete accounting. The project aimed to expand 

the range of ecological changes that were valued, 

focusing on those changes in ecosystems and services 

likely to be of greatest concern to the population. The 

study monetized the economic benefits from a variety 

of ecosystem services, including flood abatement, 

biodiversity maintenance (represented by improvement 

of avian and salmon habitat), air quality improvement, 

water quality improvement (measured by reduction of 

water temperature), and cultural services (which the 

study defined as including the creation of recreational 

opportunities and increase of property values).

The project commissioned both biophysical and 

economics analyses. The biophysical analyses included 

studies of hydrology and flooding potential, water 

quality, water temperature, habitat for salmon and other 

aquatic species, habitat for birds and other terrestrial 

species along riparian buffers, and air quality impacts 

(ozone, sulfur dioxide, carbon monoxide, carbon, and 

particulates). The economic analyses included studies 

of the impact of ecosystem changes on property values 

(including public infrastructure and residential and 

commercial property), flood risks, recreation, and 

human health. 

The project used an approach that closely resembles 

the ecological production function approach advocated 

in this report The approach linked management changes, 

such as flood project alternatives, to a range of ecological 

changes. These ecological changes were then analyzed 

for their effect on various ecosystem services. Finally, 

the analysis attempted to economically value the changes 

in ecosystem services. Although conducted by separate 

teams, the project closely linked the ecological analyses 

and economic valuation. 

Of particular note was the emphasis on estimating 

the change in values that would occur under various 

management alternatives. Rather than provide a 

static description of current conditions, which is the 

predominant form of information collected by Chicago 

Wilderness, Portland’s approach tried to estimate causeand-effect relationships that would allow the systematic 

appraisal of alternative policy or management decisions. 

This focus, along with a systems approach capable of 

incorporating multiple economic benefits, made this an 

effective vehicle to study the net economic benefits of 

alternative management options. 

The Portland study illustrates a number of good 

practices in conducting an integrated, regional-level 

analysis. The project solicited input from the public 

and important stakeholder groups in the design of 

the project so that it captured the impacts of greatest 

interest to the public. The project presented its results 

with a graphical interface that allowed stakeholders 

to run scenarios and see the resulting impacts based 

on underlying biophysical and economic models. The 

analysis effectively deployed existing methods and 

estimates, although it did not attempt to develop or test 

new approaches or methods. 

The project also illustrates some of the potential 

problems and limitations in undertaking detailed 

quantitative landscape-scale analysis. Inevitably, there 

are gaps in data and understanding in this type of 

analysis. Gaps in understanding include how changes 
86

in management actions will affect ecological systems, 

and how this will affect the provision of ecosystem 

services and consequent value. For example: How will 

songbird populations change in response to changes in 

the amount and degree of habitat fragmentation? What is 

the value to residents of Portland of changes in songbird 

populations? Because of a lack of local information, 

the study often had to use economic benefits transfer, 

drawing on cases quite different from the Portland 

context to generate estimates of values. 

The project was commissioned by the City of 

Portland and although it had minimal EPA involvement, 

the project is a good example of the type of systematic 

and integrated approach to valuing the protection of 

ecosystems and services recommended by this report. 

The project aptly illustrates the sequence of steps, from 

public input, to characterizing change in ecosystem 

functions under various policy and management options, 

to valuation of services under these alternatives. The 

project shows the great potential that this type of analysis 

offers in providing important and useful information to 

decision makers. 

6.2.3.2 Southeast ecological framework project

The Southeast ecological framework (SEF) project 

represents a regional geographic information system 

(GIS) approach for identifying important ecological 

resources to conserve. The Southeast region, which 

encompasses Alabama, Florida, Georgia, Kentucky, 

Mississippi, North Carolina, South Carolina, and 

Tennessee, is one of the fastest growing regions in 

the country, yet it still harbors a significant amount 

of globally important biodiversity and other natural 

resources. The SEF seeks to enhance regional planning 

across political jurisdictions and help focus federal 

resources to support state and local protection of 

ecologically important lands. The Planning and Analysis 

Branch of EPA Region 4 and the University of Florida 

completed the work in December 2001. 

The SEF created a new regional map of priority 

natural areas and connecting corridors, along with GIS 

tools and spatial datasets. The project also identified 43 

percent of this land that should be protected and managed 

for its specific contributions to human well-being. The 

project developed additional applications for conservation 

planning at the sub-regional and local scales. 

The SEF offers a good tool to carry out regional 

analysis of ecological components, particularly habitat 

conservation. The SEF focused narrowly on conservation 

value, defined as the ability to sustain species and 

ecological processes. Because of its focus, the level of 

scientific knowledge underpinning the SEF is, in general, 

far higher than in the other case studies examined here. 

The SEF, however, does not reflect the broad, 

integrated approach to valuation recommended by this 

report. The SEF focuses almost exclusively on habitat 

conservation rather than on a broad suite of ecosystem 

services. The SEF did not undertake extensive public 

involvement to determine its objective; it started with a 

focus on habitat conservation. It also did not attempt to 

combine its ecological analysis with an effort to value the 

protection of ecosystems or services in monetary or other 

terms. An important challenge facing regional analysis, 

particularly at a broad scale like the eight-state Southeast 

region, is how to incorporate all of these essential 

elements – a rigorous ecological approach capable of 

showing the range of ecological impacts from alternative 

policy and management decisions, public involvement and 

input on what consequences are of greatest importance to 

them, and rigorous evaluation of changes in value under 

alternative decisions.

6.2.4 Summary and recommendations

Regional-scale analysis holds great potential to 

inform decision makers and the public about the 

value of protecting ecosystems and services. Recent 

increases in publicly available, spatially-explicit data 

and a parallel improvement in the ability to display 

and analyze such data make it feasible to undertake 

comprehensive regional-scale studies of the value of 

protecting ecosystems and services. Municipal, county, 

regional, and state governments make many important 

decisions affecting ecosystems and the provision of 

ecosystem services at a regional scale, but local and state 

governments rarely have the technical capacity or the 

necessary resources to undertake regional-scale analyses 

of the value of ecosystems or services. Regional-scale 

partnerships between EPA regional offices, local and state 

governments, regional offices of other federal agencies, 

environmental non-governmental organizations, and 

private industry could aid both EPA and regional partners. 

Such partnerships offer great potential for improving the 

science and management for protecting ecosystems and 

enhancing the provision of ecosystem services. 

At present, however, this potential is largely 

unrealized. Valuation of ecosystems and services 

has not been a high priority for EPA regional offices 

largely because of tight agency budgets and the lack 

of specific legal mandates and authority. To date, 

regional offices have not undertaken the valuation 

of ecosystems and services at a regional scale in a 

comprehensive or systematic fashion. As the case studies 

have shown, however, various regional EPA offices and 

local governments have pursued some innovative and 

promising directions despite limited budgets and lack of 

specific mandates. 

The committee sees great value in undertaking a 

comprehensive and systematic approach to valuing 

ecosystems and services at a regional scale. Realizing 

the great potential of regional-scale analyses, however, 

will require a significant increase in resources for 

regional offices and, in some cases, a somewhat different 

mode of operation. To reach the potential for regional-
87

scale analysis of the value of ecosystems and services, 

the committee recommends that: 

o EPA should encourage its regions to engage in 

valuation efforts to support environmental decision 

making, following the recommendations of this report.

o EPA regional staff should be given adequate 

resources to develop expertise necessary to undertake 

comprehensive and systematic studies of the value 

of protecting ecosystems and services. Increased 

expertise is needed in several areas: 

	 • Economics and social science: Expertise is very 

limited at the regional level to undertake economic 

or other social assessments of value. A pressing 

need exists to increase expertise in this area among 

regional offices.

• Public involvement processes.

• Ecology: Regional staffs have greater expertise 

in ecology than in public involvement processes 

economics, or other social sciences, but doing 

systematic valuations of ecosystem services will 

require additional ecological staff. Of greatest 

utility would be ecologists with expertise in 

assessing impacts on ecosystem services through 

ecological production functions to evaluate 

alternative management options.

o A systematic and comprehensive approach to valuing 

the protection of ecosystems and services requires that 

ecologists and other natural scientists work together 

with economists and other social scientists as an 

integrated team. Regional-scale analysis teams should 

be formed to undertake valuation studies. Teams 

composed of social scientists and natural scientists 

should participate from the beginning of the project to 

design and implement plans for public involvement, 

ecological production functions, and valuation. 

o Gathering public input is of great importance in 

establishing the set of ecological consequences 

of greatest importance to the community. Where 

feasible, all regional-scale analyses of the value of 

ecosystems and services should involve the public at 

an early stage to ensure that subsequent ecological, 

economic, and social analyses are directed toward 

those ecosystem components and services deemed 

of greatest importance by affected communities. 

Generally, the process should proceed bottom-up, 

as opposed to top-down. Rather than asserting what 

is valuable, EPA must seek to understand what 

an informed public views as being valuable. An 

important question that should be addressed by EPA 

regional offices is how to develop effective public 

involvement at broader regional scales. 

o Some EPA staff have expressed a desire to be 

provided a value for an ecosystem component or 

service that they can then apply to their region (e.g., a 

constant value per acre of wetland or wildlife habitat). 

Such short cuts to the valuation process are uninformed 

by local social, economic, and ecological conditions 

and can generate results that are not meaningful. This 

approach to valuation should be avoided. 

o Regional staffs need to be able to learn effectively 

from valuation efforts being undertaken by other 

regional offices and by work within EPA’s Office of 

Research and Development. EPA regional offices 

should document valuation efforts and share them 

with other regional offices, The National Center 

for Environmental Economics, and EPA’s Office of 

Research and Development (which should in turn 

collaborate with the regional offices). Each regional 

office should also publish its studies. 

o Future calls by the Agency for extramural research 

should incorporate the research needs of regional 

offices for systematic valuation studies. Doing so will 

maximize the probability that future grant funding 

will be useful for EPA’s regional offices. 

o Regional staff should form partnerships with local 

and state agencies or local groups where doing so 

advances the mission of EPA directly or indirectly by 

promoting the ability of partner organizations to value 

the effect of their actions on ecosystems and services 

and to protect environmental quality. 

6.3 Valuation for site-specific decisions

6.3.1 Introduction

The Environmental Protection Agency makes many 

decisions at the local level, including the issuance of 

permits (air, water, and waste), policies that influence the 

boundaries for establishing permits (e.g., impaired water 

bodies designations), and administrative orders related to 

environmental contamination. The social and ecological 

implications of such decisions, like the decisions 

themselves, generally are local in nature, affecting 

towns, townships, and counties rather than entire states 

or regions. Therefore, the decision processes need to rely 

on valuation approaches that also are local in nature and 

are robust enough to adapt to a range of local ecological 

conditions and public interests. 

In this section, the committee focuses on the 

regulatory processes associated with one set of local 

decisions: the remediation and redevelopment of 

historically contaminated sites. That focus includes 

the Superfund program and its efforts to assess the 

contributions to human well-being from ecosystem 

services related to site remediation and redevelopment 

efforts (Davis, 2001; Wilson, 2004). As part of this 

committee’s study, the SAB staff, with assistance from 

the Agency’s National Regional Science Council, 

surveyed the regional offices to assess their needs for 

valuation information. Seven of the eight responding 

regions indicated that they need information to help 
88

value the protection of ecosystems in the management 

and remediation of contaminated sites (EPA Science 

Advisory Board Staff, 2004). The discussion that follows 

is applicable to any remediation and redevelopment 

processes for contaminated properties that contain the 

following elements:

o Identification, selection, and prioritization of sites 

o Site characterization – establishment of site condition

o Site assessment – evaluation of risks and impacts 

o Selection of remedial and redevelopment approaches

o Performance assessment of clean up and 

redevelopment

o Public communication of assessment results as well 

as proposed actions and outcomes 

This section explores how valuation methods can 

positively influence individual steps in a remediation 

and redevelopment process and lead to a better 

outcome. As appropriate, the section identifies and 

discusses individual valuation approaches or methods 

relevant to specific steps. The section builds on a 

white paper funded by EPA’s Superfund Program to 

evaluate the potential of valuation for redevelopment 

of contaminated sites (Wilson, 2004). The white paper 

assessed the improvement in ecosystem services and 

implied ecological value from the remediation and 

redevelopment of Superfund sites. Although the Wilson 

paper did not perform a formal valuation for any 

redeveloped property, it provides a useful starting point 

for exploring the utility of valuation methods in the 

remediation and redevelopment process. For his analysis, 

Wilson reviewed approximately 40 Superfund cases 

before selecting three case studies that represent urban 

(Charles-George landfill), suburban (Avtex Fibers), and 

exurban (Leviathan Mine) environments. This section 

analyzes and relies on these same three cases, as well as 

an additional urban example, the DuPage landfill, which 

provides a useful counterpoint to the Charles-George 

landfill example. The DuPage example shows how an 

early focus on ecosystem services can better identify 

potential ecosystem services that can be targeted during 

the remediation and restoration phases. A brief overview 

of each of these cases appears in section 6.3.2. 

6.3.2 Opportunities for using valuation to inform 

remediation and redevelopment decisions

The Superfund process and its individual steps or 

stages are well defined (EPA CERCLA Education 

Center, 2005). Superfund and related remediation 

processes are focused on first defining a problem, then 

characterizing and assessing its potential and actual 

human health and environmental impacts, and finally 

developing and executing a technical strategy to alleviate 

or avoid those impacts. Since 1985, EPA’s Brownfield 

Program has integrated consideration of upstream 

redevelopment into the remediation process (EPA, 

2004b). The Agency developed the reuse assessment tool 

to integrate land use into the Superfund process (Davis, 

2001). Integrating remediation and redevelopment 

demonstrates the need to consider ecological valuation 

into all steps and stage from the very beginning.

Figure 5 illustrates how valuation information can be 

integrated into the traditional process for remediation 

and redevelopment. In the committee’s view, EPA 

and the community should define at the outset what 

the potential site should be after remediation and 

redevelopment and what ecological services are to be 

preserved, restored, or enhanced for use by the local 

community. This differs from the more traditional 

practice. This practice initially focuses on the type, 

degree, and extent of chemical contamination, and then 

on the human and ecological receptors currently exposed 

and therefore at risk under current chemical conditions. 

In the traditional approach, the data collection for 

site characterization captures the degree and pattern of 

chemical contamination but does not collect information 

about the ecological condition of the site or the value 

of any services associated with the site in its current 

or proposed future conditions. In the traditional 

approach, moreover, the conceptual model that defines 

the exposure pathways to key receptors and therefore 

guides the design of the risk analysis is based on current 

rather than future conditions. This can lead to a risk 

assessment that selects receptors that are sensitive under 

current conditions but may not be sensitive or important 

under alternative future uses. This logic focuses remedy 

evaluation and selection on controlling the risks under 

current use. In the end, the traditional approach assumes 

that risk reduction and management, rather than the 

optimized reuse value for the community, are the 

ultimate performance goals. Such an approach may 

leave the community feeling that the risk is gone but still 

dissatisfied with the values gained by the cleanup. 

Integrating future use considerations into the 

remediation process and focusing on value generation 

will lead to outcomes that better satisfy the public. To 

accomplish this metamorphosis, it is essential to find 

ways to introduce estimates of ecosystem services 

and values into management strategies and associated 

analytical processes. Early recognition of future uses 

and the ecosystem services that matter to people can 

inform site assessment and the ultimate selection of 

remedial actions and redevelopment options. Identifying 

expected or actual contributions to human well-being 

can also lead to more effective communication with the 

affected public. The rest of this section discusses the 

opportunities and utility of adapting valuation methods 

to this more integrated and forward-looking assessment 

and redevelopment process.

Valuation methodologies are important first in 

identifying how a site and its current or potential 
89

ecosystem services matter to the surrounding 

community. EPA should use valuation methods 

to determine how the site has contributed and can 

contribute to human well-being and how potential 

effects on ecological components may diminish those 

contributions. When the ecosystem services that 

matter to people are well-defined and when ecological 

risk assessments are coupled with these services, the 

remediation and redevelopment plan can target what 

matters to the local community. A key recommendation, 

therefore, is that EPA consider ecosystem services 

and their contributions to human well-being and 

other values from the earliest stages of addressing 

contaminated properties. 

Even as early in the management process as site 

selection or prioritization, tools that can compare 

the potential of sites to provide ecosystem services 

could be informative. The contribution of ecological 

protection to human well-being should be considered 

Figure 5: Integration of valuation information with the traditional remediation and 

redevelopment process

Site

Identification

Site

Characterization

Site

Assessment

Remedy

Selection

Remedial

Action Defined

Site

Redevelopment

Performance

Assessment

Data collected could include 

ecological condition and 

community preference for 

ecosystem services from 

future use options

Assessment focuses on 

risks relevant to planned 

future uses and ecosystem 

services

Remedy optimized for 

redevelopment and 

consideration of ecological 

reuse

More cost-effective

redevelopment strategies

Greater public understanding 

of benefits and support for 

project

Lessons learned captured 

to improve future project 

execution

Future use analysis

including ecological and 

commercial uses

Align analytical endpoints 

with future use and 

ecosystem services

Consider opportunities 

to integrate remedial and 

redevelopment actions

Compare cost and benefits 

of remedial alternatives

Communicate proposed 

actions and expected 

outcomes to public

Document benefits 

delivered

Value Inputs Change to Current Practice
90

in the design of any site characterization plan. A typical 

site characterization focuses on the aerial extent of 

chemicals and their range of concentration in site media 

(e.g., ground and surface water, soil, and biological 

tissue). A plan that also collects information to define 

and assess ecosystem services would better align 

ecological-risk assessments with economic benefits and 

other contributions to human well-being. Aligning risk 

assessments and assessments of contributions to human 

well-being should be a critical objective for the Agency. 

Alignment will help ensure that remedial actions 

address the restoration of contributions to human wellbeing derived from important ecosystem service flows 

that have been diminished or disrupted. Aligning risk 

assessment endpoints with ecosystem services should 

also result in multiple benefits, including: 

o Improved alignment with community goals

o Improved ability to perform meaningful assessments 

of economic benefits and other contributions to 

human well-being

o Improved ability to communicate proposed actions

o Improved ability to monitor and demonstrate 

performance

Successfully remediating and redeveloping 

contaminated sites depends in great part on the degree 

to which efforts either protect or restore ecosystem 

services that contribute to human well-being. If values 

have been broadly explored and effectively integrated 

into site assessment and remedy-selection processes, 

appropriate measures of performance will be apparent. 

Ecological measures of productivity or the aerial extent 

of conditions directly linked to valued ecosystem 

services will be useful in tracking the performance of 

remediation and redevelopment processes. Advancing 

the Agency’s capability to evaluate performance both in 

real time and retrospectively will help the Agency better 

justify its overall performance record in the remediation 

and redevelopment of contaminated sites. 

Finally, the remediation and redevelopment of a 

property encompasses more than just the science and 

engineering that historically have underpinned the 

remediation process. Effective communication with 

members of the public actively participating in the 

Text box 4 – Charles-George Landfill: An urban example

From the late 1950s until 1967, the Charles-George Reclamation Trust Landfill, located one mile 

southwest of Tyngsborough and four miles south of Nashua, New Hampshire, was a small municipal dump. 

A new owner expanded it to its present size of approximately 55 acres and accepted both household and 

industrial wastes from 1967 to 1976. The facility had a license to accept hazardous waste from 1973 to 

1976 and primarily accepted drummed and bulk chemicals containing volatile organic compounds (VOCs) 

and toxic metal sludges. Records show that over 1,000 pounds of mercury and approximately 2,500 cubic 

yards of chemical wastes were landfilled. The state ordered closure of the site in 1983. That same year, EPA 

listed the site on the National Priorities List (NPL) and the owner filed for bankruptcy. Samples from wells 

serving nearby Cannongate Condominiums and some nearby private homes revealed VOCs and heavy metals 

in the groundwater. Approximately 500 people lived within a mile of the site in this residential/rural area; 

2,100 people lived within three miles of the site. The nearest residents were located 100 feet away. Benzene, 

tetrahydrofuran, arsenic, 1,4-dioxane, and 2-butanone, among others, had been detected in the groundwater. 

Sediments had been shown to contain low levels of benzo(a)pyrene. People faced a potential health threat by 

ingesting contaminated groundwater. Flint Pond Marsh, Flint Pond, Dunstable Brook, and nearby wetlands 

were threatened by contamination migrating from the site. 

EPA’s involvement at the site began with groundwater testing conducted by an EPA contractor during 1981 

and 1982. The site was proposed for the NPL on October 23, 1981, and finalized on the NPL in September 

1983. In September 1983, EPA also allocated funds for a removal action at the site to replace the state’s 

Department of Environmental Quality Engineering temporary water line with another temporary but insulated 

water line. Other removal work included construction of a security fence along the northwestern entrance to 

the landfill, regrading and placement of soil cover over exposed refuse, and installation of twelve gas vents. 

A remedial investigation and feasibility study was also begun in September 1983. The basis for the removal 

action was documented in the first record of decision issued on December 29, 1983.

EPA Web site history

http://yosemite.epa.gov/r1/npl_pad.nsf/f52fa5c31fa8f5c885256adc0050b631/ABD286D719D254878525690

D00449682?OpenDocument
91

Text Box 5 – DuPage County Landfill: An urban example

The 40-acre tract of land that is the Blackwell Landfill was originally purchased by the DuPage County 

Forest Preserve District (FPD) in 1960 and is centrally located within the approximately 1,200-acre 

Blackwell Forest Preserve, about 30 miles outside Chicago, Illinois. The landfill was constructed as a 

honeycomb of one-acre cells lined with clay. Approximately 2.2 million cubic yards of wastes were deposited 

in the landfill between 1965 and 1973. The principal contaminants of concern for this site were the volatile 

organic compounds (VOCs) 1,2-dichloroethene, trichloroethene and tetrachloroethene, detected in onsite 

groundwater at or slightly above the maximum contaminant level (MCL). Landfill leachate contained all 

kinds of VOCs and semivolatiles including benzene, ethylbenzene toluene, and dichlorobenzene, as well 

as metals such as lead, chromium, manganese, magnesium, and mercury. VOCs and agricultural pesticides 

had also been detected in private wells down gradient of the site but at low levels. Some metals (manganese 

and iron) had been detected above the MCLs in down-gradient private wells. Post-remediation, the site now 

consists mainly of open space, containing woodlands, grasslands, wetlands, and lakes, used by the public for 

recreational purposes such as hiking, camping, boating, fishing, and horseback riding. There are no residences 

on the FPD property, and the nearby population is less than 1,000 people. The landfill created Mt. Hoy, which 

is approximately 150 feet above the original ground surface. 

EPA Web site history

http://cfpub.epa.gov/supercpad/cursites/csitinfo.cfm?id=0500606

remedial and redevelopment process and with the 

general public is a critical element in the success of 

the management process. Both of these audiences 

bring values to the table when they evaluate proposed 

actions or the results of any action taken. A strong 

alignment between the ecosystem services valued by 

these audiences and expected or actual outcomes will 

facilitate effective remediation and redevelopment.

6.3.3 Illustrative site-specific examples

The following analysis applies the general 

recommendations of chapter 2 to the site-specific 

level. The committee illustrates these site-specific 

recommendations with lessons gleaned from a series 

of Superfund examples in urban (Charles-George and 

DuPage landfills), suburban (Avtex Fibers) and ex-urban 

(Leviathan Mine) contexts. The backgrounds on each of 

these cases appear in text boxes 4-7.

6.3.3.1 Determining the ecosystem services 

important to the community. 

The urban examples of the Charles-George and 

DuPage County landfills show the value of engaging 

with the community at an early stage to determine the 

ecosystem services of importance to them. Although 

neither landfill apparently used formal valuation methods 

at the outset, DuPage County’s focus on ecosystem 

services and the inclusion of additional experts (i.e., 

forestry experts) led to a more positive outcome. 

At the Charles-George landfill, EPA did not consider 

ecological values or future uses at the start. The human 

health risks at this site were so salient at the time that they 

were the focus of subsequent decisions. EPA addressed 

the health and safety risks by capping the landfill site 

and extending the water system from the city of Lowell, 

Massachusetts, to the affected community. Although 

EPA published the record of decision more than 20 years 

ago, the site is still a fenced-off no-man’s land, and the 

potential for ecosystem services remains untapped. 

By contrast, the remediation and redevelopment of 

the DuPage County landfill site appears to have been 

motivated largely by the need to address existence 

values (e.g., the presence of hawks and other rare birds) 

and recreational values (e.g., hiking, bird watching, 

boating, camping, picnicking, and sledding). The 

remediation effort succeeded, and the site is now part 

of the Blackwell Forest Preserve. Listed as a Superfund 

site in 1990, “a once dangerous area is now a community 

treasure, where visitors picnic, hike, camp, and take boat 

rides on the lake” (EPA, 2004c).

The urban examples show that even the most 

rudimentary dialogue about future use can lead to an 

outcome with greater service to the community. At the 

DuPage landfill site, a qualitative focus on the utility 

of ecosystem services led to the recognition that in a 

very flat landscape, even a 150-foot hill, if properly 

capped and planted, would be a welcome refuge 

for people as well as wildlife. The DuPage Forestry 

District understood the ecological potential of the area, 

particularly for hawks, and recognized that, where hawks 

abound, birders will come to watch them. The difference 

was one not of methodology but of conception. 

In working with the Avtex Fibers site (described 

in text box 6), a suburban location, EPA also engaged 

key members of the public. After the site was listed 

and a management process established, EPA undertook 

a clear effort to engage the public through a multistakeholder process in the development of the master 
92

Text box 6 – Avtex Fibers site: A suburban example

The Avtex Superfund site consists of 440 acres located on the bank of the Shenandoah River within the 

municipal boundaries of Front Royal, Virginia. The site is bordered on the east by a military prep school, 

on the south by a residential neighborhood, and on the west by the Shenandoah River. From 1940 to its 

closure in 1989, industrial plants on the site manufactured rayon and other synthetics. Tons of manufacturing 

wastes and byproducts accumulated on the site, infiltrated into groundwater under the site, and escaped 

into the Shenandoah River. The Avtex Fibers site was proposed for inclusion on the National Priorities 

List on October 15, 1984, and the site was formally added to the list on June 10, 1986. EPA began removal 

activities at the site in 1989 to address various threats to human health and the environment. The cleanup 

and restoration plan called for most remaining wastes to be consolidated on site, secured with a protective 

material where needed, and covered by a thick cap of soil and vegetation. 

Front Royal is close to the Appalachian Trail, Shenandoah National Park, and George Washington National 

Forest, and a number of significant Civil War sites, making it a major tourist center for the Blue Ridge 

Mountains. Biologically, the Avtex site contains some residual forested areas, open meadows, small wetland 

areas, and more than a mile and a half of frontage along the Shenandoah River. The proposed master plan for 

redevelopment, created through a formal multi-stakeholder process, divides the site into three areas: a 240-

acre river conservancy park along the Shenandoah River combining ecological restoration and conservation of 

native habitats; a 25-acre active recreation park with boat landings, picnic shelters, and a developed recreation 

area including a visitor center and soccer fields; and a 165-acre eco-business park, featuring the refurbished 

historic former Avtex administration building. Cleanup of the Axtex site is ongoing, and the redevelopment 

plan is being actively pursued by local government agencies and private industry groups.

EPA Web site history

http://www.epa.gov/superfund/accomp/success

/avtex.htm

Stakeholders’ Avtex Fibers Conservancy Park Master Plan

http://www.avtexfibers.com/Redevelopment/avtexWEB/avtex-Mp.html

Text box 7 – Leviathan Mine Superfund site: An ex-urban example

In May 2000, the EPA added the Leviathan Mine site in California to the National Priority List of 

Superfund sites. The site is currently owned by the state, but from 1951 until 1962 the mine was owned and 

operated by the Anaconda Copper Mining Company (a subsidiary of ARCO) as an open pit sulfur mine. The 

mine property is 656 acres in a rural setting near the Nevada border, 24 miles southeast of Lake Tahoe. The 

mine itself physically disturbed about 253 acres of the property plus an additional 21 acres of National Forest 

Service land. The site is surrounded by national forest. In addition, it lies within the aboriginal territory of the 

Washoe Tribe and is close to several different tribal areas. 

The mine has been releasing hazardous substances since the time that open pit mining began in the 1950s. 

Releases occur through a number of pathways, including surface water runoff, groundwater leaching, and 

overflow of evaporation ponds. In particular, precipitation flowing through the open pit and overburden and 

waste rock piles creates acid mine drainage (AMD) in the form of sulfuric acid, which leaches heavy metals 

(such as arsenic, cadmium, copper, nickel, and zinc) from the ore. These releases are discharged into nearby 

Leviathan Creek and Aspen Creek, which flow into the East Fork of the Carson River. Pollution abatement 

projects have been underway at the site since 1983. Despite these efforts, releases continue today. 

The releases of hazardous substances from the mine have significantly injured the area’s ecosystem and 

the services it provides. In the 1950s, structural failures at the mine that released high concentrations of AMD 

into streams resulted in two large fish kills, and the trout fishery downstream of the mine was decimated 

during this time. More recently, data have documented elevated concentrations of heavy metals in surface 

water, sediments, groundwater, aquatic invertebrates, and fish in the ecosystem near the site. This suggests 

(continued)
93

plan. Although there was some consideration of 

ecosystem services, EPA does not appear to have 

engaged in any systematic efforts to assess the services 

that people cared the most about. 

For sites like Avtex Fibers, deliberative group processes 

involving the public and relevant experts, including 

historians, could help identify and document ecosystem 

services of most concern to the public. In framing the 

dialogue with members of the public, methods such as 

ecosystem benefits indicators or the conservation value 

method might help EPA’s site managers understand the 

ecosystem-service potential of future uses. Those methods 

could also provide inputs for further valuation using other 

methods described in chapter 4 (e.g., economic methods 

or decision science approaches).

The Leviathan Mine case, described in text box 7, 

illustrates how EPA often must consider a complex 

array of competing interests. The Agency in this 

case faces a clear dichotomy between the ecosystem 

services valued by the full-time resident population 

of American Indians and by occasional recreational 

users. Recreational users would gain from services 

associated with hiking, fishing, and camping. The 

Washoe Tribe, however, values the ecosystem as 

a provisioning service for food as well as for its 

spiritual and cultural services. 

The Leviathan Mine case also highlights the need 

to consider the existence or intrinsic values of an 

ecosystem. The ecosystem near the Leviathan Mine 

provides a habitat for threatened species such as the 

Lahontan cutthroat trout and bald eagle. In considering 

site restoration or remediation, or in measuring 

damages from contamination at the mine, the Agency 

could miss the primary sources of value if it limited 

consideration to use value and did not consider 

existence or intrinsic value. 

For the Leviathan Mine example, EPA could obtain 

information about the impacts of greatest concern to 

that hazardous substances have been transmitted from abiotic to biotic resources through the food chain, 

thereby affecting many trophic levels. A recent assessment identifies seven categories of resources potentially 

impacted by the site: surface water resources, sediments, groundwater resources, aquatic biota, (including the 

threatened Lahontan cutthroat trout), floodplain soils, riparian vegetation, and terrestrial wildlife (including 

the threatened bald eagle). These uses, in turn, help support recreational uses (including fishing, hiking, and 

camping); and tribal uses (including social, cultural, medicinal, recreational, and subsistence).

The process of determining compensatory damages and developing a response plan involves a number 

of different stages for which information about the value of these lost services would be a useful input. 

For example, in accordance with the Natural Resource Damage Assessment (NRDA) regulations under the 

Comprehensive Environmental Response, Compensation and Liability Act, the trustees for the site conducted 

a pre-assessment screening to determine the damages or injuries that may have occurred at the site and 

whether a natural resource damage assessment should be undertaken. This required a preliminary assessment 

of the likelihood of significant ecological or other impacts from the contamination (corresponding to step 2 in 

figure 1 of this report). 

The decision was made in July 1998 to move forward with a Type B NRDA and thus to assess the value 

of the ecosystem services that have been lost as a result of the site contamination. A Type B assessment 

involves three phases: an injury determination to document whether ecological damages have occurred; a 

quantification phase to quantify the injury and reduction in services (corresponding to step 4 of figure 1); and 

a damage determination phase to calculate the monetary compensation that would be required (corresponding 

to step 5 of figure 1). 

In the Leviathan Mine case, the trustees proposed using resource equivalency analysis based on a 

replacement cost estimate of the lost years of natural resource services to determine damages for all affected 

services other than non-tribal recreational fishing. For this latter ecosystem service, they proposed using 

economic benefit transfer to estimate the value of lost fishing days. In the decision by EPA whether to list the 

site on the NPL and in the subsequent record of decision selecting a final remedy for the site, information about 

the value of the ecological improvements from cleanup could play an important role, although these decisions 

have often been based primarily on human health considerations. 

EPA Web site history 

http://www.epa.gov/superfund/sites/npl/nar1580.htm

Leviathan Mine National Resource Damage Assessment Plan, 

http://www.fws.gov/sacramento/ec/Leviathan%20NRDA%20Plan%20Final.pdf
94

affected individuals in at least three ways. The first 

would be to gather information about the relative 

importance of the various services directly from 

affected individuals through focus groups, mental 

models, mediated modeling, deliberative processes, 

or anthropological or ethnographic studies based on 

detailed interviews. The second approach would be 

to gather basic information that could indicate the 

importance of different services. This information 

might be of the type used to construct ecosystem benefit 

indicators: water use data for the Washoe tribe and 

others in the vicinity of the site (e.g., sources, quantities, 

and purposes), harvesting information for the Washoe 

(e.g., what percent of their harvesting of nuts, fish, etc., 

comes from the area affected by the site), recreational 

use data (e.g., the number of people visiting the local 

national forest for hiking, camping, fishing, and wildlife 

viewing), data on flooding potential and what is at risk 

in the vicinity of the site, and data on spiritual/cultural 

land-use practices by the Washoe. The third approach 

would be to review related literature and previous studies 

to learn about impacts of concern in similar contexts. 

For example, previous social/psychological surveys not 

specific to this site or other expressions of environmental 

preferences (e.g., outcomes of referenda or civil court 

jury awards) might provide insight into what people are 

likely to care about in this context. Similarly, previous 

contingent valuation studies of existence value might 

provide some, at least partial, indication of the likely 

importance of impacts on species such as bald eagles. 

Likewise, previous studies of the value of recreational 

fishing (e.g., from travel cost models) could be coupled 

with use data to provide an initial indication of the 

importance of the impact on recreational fishing.

6.3.3.2 Involving interdisciplinary experts 

appropriate for valuation.

Interactions among experts and the affected public 

form a key component of any program of hazardous 

site assessment, planning, and implementation. Ideally, 

collaboration among all relevant experts, including 

physical, chemical, and biological scientists (e.g., 

ecologists and toxicologists) and social scientists (e.g., 

economists, social psychologists, and anthropologists), 

as well as communication with affected publics, 

must begin very early in the planning stages of 

remediation and redevelopment and continue throughout 

implementation and post-project monitoring and 

evaluation. Key areas for collaboration among experts 

are the development of alternative management scenarios 

and the translation of physical and biological conditions 

and changes into value-relevant outcomes that can be 

communicated to the public. 

The Leviathan Mine illustrates the need for 

collaboration among multiple disciplines to understand 

how the population’s values are affected. Because of 

the unique cultural and spiritual values associated with 

the site, anthropologists could play an important role 

in characterizing the value of the ecosystem services 

to the Washoe Tribe. Economists or others seeking to 

estimate existence value for an affected species would 

need to work closely with ecologists to determine the 

likely impact of any change or proposed project on that 

species so that the change could be readily valued. 

6.3.3.3 Constructing conceptual models that 

include ecosystem services 

Ecological assessments associated with the 

remediation and redevelopment of contaminated 

property will better aid decision making if they 

incorporate ecological production functions that link 

remediation and redevelopment actions to ecosystem 

services. None of the four sites chosen by the committee 

conducted such assessments. Both the DuPage County 

landfill and the Aztex Fibers cases appear to have 

qualitatively considered ecosystem services, with 

commendable results, illustrating how more formal 

assessments using ecological models and production 

functions could further improve site-specific remediation 

and redevelopment efforts.

Although it is now standard practice to develop 

a conceptual model in performing ecological risk 

assessments for contaminated sites, EPA’s analyses of 

adverse impact have generally not linked to ecosystem 

services. The primary focus of the Agency’s remediation 

efforts has been to control anthropogenic sources of 

chemical, biological, and physical stress that could lead 

to adverse impacts to human health or the environment. 

Developing conceptual models that incorporate the 

linkage between ecological endpoints and communityidentified services would better guide both for the 

valuation of ecological protection and site remediation 

and redevelopment.

The Avtex Fiber case highlights what EPA could 

gain from developing the capacity to use conceptual 

models that integrate ecological effects and ecosystem 

services. A noteworthy feature of the Avtex Fiber 

process was the development of a master plan, which 

included some consideration of ecosystem services. 

For example, early concerns about contamination of 

groundwater and the discharge of toxic substances 

into the Shenandoah River focused attention on 

water quality. Aquatic basins constructed to contain 

contaminants on site were designed to restore 

important ecosystem services, including safe habitat 

for waterfowl, runoff control, and water purification 

services. In this regard, the plan implied but failed 

to quantify or document a rudimentary ecological 

production function. 

The development of a conceptual model that 

incorporated ecosystem services would have 

systematically facilitated greater integration of 

ecosystem services into remedial design and future 
95

uses. Recreational and aesthetic services were clearly 

important considerations for many features of the 

plan. However, because no comprehensive ecological 

model identifying ecosystem services apparently 

guided redevelopment at the site, it is unclear whether 

the particular pattern of restored forests and wetlands, 

recreation areas, and industrial parks produced the 

most valuable protection for ecosystem services. 

Different siting and design of soccer fields, for 

example, might have provided the same recreational 

value while achieving greater wildlife habitat, water 

quality, or aesthetic values for visitors, nearby 

residents, or both. The master plan’s declared green 

focus for the industrial park implied that ecological 

concerns were important in the selection of industrial 

tenants and in the siting and design of facilities, 

but no ecological model for achieving this goal, 

or monitoring progress toward it, was presented. 

This omission leaves open the prospect that future 

industrial, recreational, and tourist developments and 

uses at the Avtex site might simply substitute one set 

of damages to ecosystems and ecosystem services for 

another.

6.3.3.4 Predicting effects on relevant ecosystem 

services

As discussed in chapter 3, development of a 

conceptual model should be followed with predictive 

analyses of the effects of EPA’s actions on ecosystem 

services. Expanding ecological risk assessments to 

include assessments of the services that matter to people 

may present technical challenges, given the current focus 

of ecological risk assessments on toxicological data for 

a limited range of species and for toxic responses from 

individuals in those species. Such data will rarely link 

well to the ecosystem services that matter to a particular 

site-specific decision. 

The Agency will need to develop its capacity to adapt 

and apply models that incorporate ecological production 

functions. These models are the real bridge between risk 

estimates and subsequent injury or damage projections 

and provide a major piece of the puzzle to quantify and 

value the impacts of chemical exposures under different 

remedial and restoration alternatives. 

Incorporating ecological production functions into 

EPA’s risk assessments will be important not only for 

EPA decisions on site remediation and redevelopment 

but also for natural resource damage assessments 

(NRDAs). Although trustee agencies, such as the 

National Oceanic and Atmospheric Administration and 

the U.S. Fish and Wildlife Service, are the regulatory 

leads for NRDAs, the ecological risk assessments and 

conceptual models produced by EPA in the remediation 

process are often the basis for damage assessment. If 

EPA could effectively conduct assessments that use 

ecological production functions to predict impacts on 

ecosystem services, those assessments would enhance 

the ability of resource trustees to assess injury, define 

restoration goals, and calculate damages. Predictive 

ecological production functions can play a critical role in 

such assessments. 

The Leviathan Mine example illustrates how 

ecological impacts and damages are currently 

assessed. The Leviathan Mine natural resource 

damage assessment plan gives detailed information 

on concentrations of key pollutants (particularly 

heavy metals such as cadmium, zinc, copper, nickel, 

and arsenic) in surface water samples, groundwater 

samples, sediment samples, samples of fish tissues, 

and insect samples at various distances from the mine 

site. These concentration levels can be compared 

to concentration levels at reference sites (because 

historical information for the site itself is not available), 

toxicity data from the literature, and existing regulatory 

standards (e.g., water quality criteria or drinking 

water standards) to evaluate the potential for impact. 

Importantly, none of these comparisons is a direct 

demonstration of injury, which can only be measured 

through field observation and tests. EPA must rely on 

surrogates to estimate impact. 

Once the impacts on water quality, sediments, etc., 

have been determined, ecological production functions 

could translate these impacts into predicted changes in 

ecosystem services. If recreational fishing is important, 

for example, EPA must estimate the site’s impact on 

the fish population in the nearby water body. Such 

an analysis would require estimating the impacts of 

changes in water quality, streambed characteristics, bank 

sediments, and riparian vegetation on fish population, 

both directly and through impacts on the insects on 

which fish feed. If elevated levels of arsenic, copper, 

zinc, or cadmium exist in insects and fish tissue, EPA 

must also be able to use this information to predict an 

overall impact on the fish population.

EPA has already developed complex ecological risk 

assessment modeling tools (e.g., TRIM, EXAMS, and 

AQUATOX) to estimate the fate and effects of chemical 

stresses on the environment. In some cases, EPA 

has even coupled such exposure-effects models with 

ecological production models to estimate population 

level effects (Nacci and Hoffman, 2006; Nacci et al., 

2002). 

In many cases, an ecological model that links 

ecological processes at a site to ecosystem services of 

interest to that site do not currently exist, although it 

might be possible to adapt models from the literature 

to fit local conditions with site-specific field data if the 

scale and ecological components of the site are similar 

(using the criteria for selecting among existing models 

described in section 3.3.1). In the absence of such a 

site-specific model, EPA might look to the scientific 

literature for guidance on how sensitive the insects and 
96

fish species are to these types of stressors. It could then 

ask expert ecologists to judge the likely magnitude 

of the impacts in the specific case. As for transfer of 

ecological benefits, however, scientists must take into 

account the differences between the reference site and 

the contaminated site and define and communicate 

the assumptions and limitations of transferring the 

information. 

The Leviathan Mine Natural Resource Damage 

Assessment Plan also suggests studying the fish 

population downstream from the mine and comparing 

it to the population in a reference location, assuming 

an appropriate reference site can be identified. More 

generally, it suggests comparing riparian vegetation, 

the composition of the benthic community, and 

wildlife populations near the mine and at an acceptable 

reference site. Such a comparison can help frame 

the types of damages resulting from the mining 

activity. Because reference sites and exposed sites 

may differ for a number of reasons not related to the 

contamination, such a comparison may not directly 

estimate the injury and will not take into consideration 

the impact of proposed remedial actions. Decisions 

about remediation and restoration require analysis 

of proposed actions, and it may not be reasonable 

to assume that remedial actions will be 100 percent 

effective in restoring relevant ecosystem services to 

their original level. 

Comparative analyses of remedial actions using 

ecological production functions are needed and 

can be facilitated through comparative tools such 

as net environmental benefit analysis (Efroymson 

et. al., 2004). This analysis provides a framework 

for using valuation tools to compare alternative 

remedial strategies based on net impacts on ecological 

services.

6.3.3.5 Defining, cataloging, and accounting for 

ecosystem services

Accounting rules are needed to avoid double 

counting or undercounting the contributions to human 

well-being from ecosystem services. Ecosystems and 

their numerous components are linked in an intricate 

and complex network of biological, chemical, and 

energy flows. A focus on isolated impacts to individual 

Text box 8 – Net environmental benefit analysis

As described by Efoymson et al. (2003), “Net environmental benefits are the gains in environmental 

services or other ecological properties attained by remediation or ecological restoration, minus the 

environmental injuries caused by those actions. Net environmental benefit analysis (NEBA) is a methodology 

for comparing and ranking the net environmental benefit associated with multiple management alternatives. 

A NEBA for chemically contaminated sites typically involves the comparison of the following management 

alternatives: (1) leaving contamination in place; (2) physically, chemically, or biologically remediating 

the site through traditional means; (3) improving ecological value through onsite and offsite restoration 

alternatives that do not directly focus on removal of chemical contamination; or (4) a combination of those 

alternatives. 

NEBA involves activities that are common to remedial alternatives analysis for state regulations and the 

Comprehensive Environmental Response, Compensation and Liability Act, response actions under the Oil 

Pollution Act, compensatory restoration actions under Natural Resource Damage Assessment, and proactive 

land management actions that do not occur in response to regulations, i.e., valuing ecological services or 

other ecological properties, assessing adverse impacts, and evaluating restoration options.”

Figure 6, taken from Efroymson et al. (2003), “depicts the high-level framework for NEBA. It includes 

a planning phase, characterization of reference state, net environmental benefit analysis of alternatives 

(including characterizations of exposure of effects, including recovery), comparison of NEBA results, 

and possible characterization of additional alternatives.” Dashed lines indicate optional processes; circles 

indicate processes outside the NEBA framework. Only ecological aspects of alternatives are included in this 

framework. “The figure also depicts the incorporation of cost considerations, the decision, and monitoring 

and efficacy assessment of the preferred alternative, although these processes are external to NEBA.” 

Because NEBA is a framework, the needed resources, data inputs, and limitations are associated with 

whatever ecological models and valuation tools are selected. 

Currently, NEBA is being applied at a local scale, although the size of some contaminated properties 

and their impacts can extend to the regional scale (e.g., impact of releases from a contaminated site to a 

watershed). NEBA should be highly adaptable to different levels of data, detail, scope, and complexity. 
97

organisms or components and their associated 

services can lead to double counting or undercounting 

contributions to human well-being generated by 

Agency actions. 

For example, the listing of services (aquatic biota 

and habitat, riparian vegetation, terrestrial wildlife, 

recreational uses, and tribal uses) in the Leviathan 

Mine case does not seem to be useful for sorting out 

the different services to be valued. The listing fails 

to identify mutually exclusive services and presents 

a high likelihood of double counting. It also does not 

adequately distinguish between inputs and outputs. 

The significance of protecting habitat and riparian 

vegetation, for example, is not clearly addressed. 

Is it because society cares about the populations 

they support? Or is it because these populations 

are an input into something else of value, such as 

recreation? Consider insect populations. If society 

cares about the insects for their own sake, the insects 

generate unique existence value. If they are valued 

Figure 6: Framework for net environmental benefit analysis (from Efroymson et al., 2003).

Integrated problem formulation

• Management and assessment goals

• Assessment endpoints (ecological services, other properties) and measures of effects

• Adverse or beneficial agents

• Temporal measures of exposure and effects

• Spatial measures of exposure and effects

• Reference state

• Comparative metrics

• Conceptual model

• Analysis plan

ecological characterization of 

uncontaminated state

Characterization of reference state(s) (services or other ecological properties)

NEBA of 

remedial

alternative

ecological characterization of contaminated 

state (natural attenuation alternative)

Net Environmental Benefit Analysis of Management Alternatives

NEBA of ecological

restoration

alternative

NEBA of combined remediation

or restoration or natural

attenuation

Integration of NEBA results to

produce improved management

alternatives

Comparison (ranking) of NEBA results,

relative to each reference state

Division of net

benefit by cost

Decision

Monitoring and

efficacy

assessment
98

as a food source for fish and society cares about fish, 

there is value in the change in fish brought about by 

the change in insects. But in the latter case, insects 

should not be valued separately.

A better delineation of ecosystem services might 

involve identifying directly experienced, measurable, 

and spatially and temporally explicit services. For the 

Leviathan Mines example, such a list of ecosystem 

services might consist of the following:

o Water used by Washoe Tribe members and others for 

washing and drinking 

o Non-consumptive uses of wildlife (e.g., viewing bald 

eagles and other species)

o Harvesting (hunting, fishing, and collecting fish) by 

Washoe tribal members

o Cultural, spiritual, and ceremonial values of land used 

by Washoe tribal members

o Flood control (e.g., reduction in flooding from 

snowmelt or runoff)

o Recreational services (e.g., fishing, hiking, and 

camping)

6.3.3.6 Expanding valuation methods

The typical comparison of remedial strategies 

currently includes two tests: whether a remediation 

action controls risk to an acceptable level, and if so, 

whether it is cost effective. Under this scheme, if a 

proposed remediation action is adequate with regard to 

risk reduction, the least costly alternative is the obvious 

choice. Such an approach decouples remediation and 

redevelopment, delays the development process, and 

may not maximize what matters to the public. 

If remediation and redevelopment alternatives are 

to be compared based on their contributions to human 

well-being, EPA must be able to value the effect of 

each alternative on ecosystem services. As mentioned 

previously, NEBA offers a conceptual framework for 

comparing remedial and redevelopment alternatives 

on the basis of their net contributions to human wellbeing, whether monetized or non-monetized. Chapter 4 

in turn describes a broad range of methods for valuing 

ecosystem services. 

Habitat equivalency analysis (HEA) provides 

one approach for comparing contributions to human 

well-being associated with different remedial and 

redevelopment alternatives. HEA reports results in 

ecological units over time (e.g., discounted service acres 

years). The cost of creating or replacing those ecological 

units in monetary terms provides a replacement cost. 

Although these approaches do not provide direct measures 

of the value of the ecosystem services, they support a 

comparison of the services provided under different 

options. Alternatively, impacts of alternatives could be 

compared purely in ecological or biophysical terms 

through a method such as the conservation value method 

EPA could also compare remediation and 

redevelopment alternatives using economic valuation. 

For example, EPA could use hedonic pricing studies 

to determine the economic impacts of the cleanup and 

redevelopment options on adjacent residential property 

values. New contingent valuation studies or studies 

using travel cost models could capture in monetary terms 

recreational or aesthetic values. Models might be used 

to compare expected gains to the local economy across 

the feasible set of redevelopment scenarios. Ecosystem 

benefit indicators, as discussed above, might also be 

used to evaluate the impacts of different remediation or 

redevelopment options. 

If members of the public are involved in testing 

remediation and redevelopment alternatives, EPA 

could use decision-aiding processes to assess their 

preferences for or weighting of alternatives. Formal 

social-psychological surveys of potential recreational 

users, visitors, and tourists could measure the relative 

preferences of these groups among remediation and 

redevelopment plans. Parallel economic or monetary 

assessments, perhaps using contingent valuation or travel 

cost methods, could extend and cross-validate survey 

results. Decision science methods could provide weights 

to facilitate analyses of tradeoffs among recreation, 

tourism, and industrial development at a site. 

6.3.3.7 Communicating information about 

ecosystems

EPA should explicitly address ecosystem services 

in communications about site remediation and 

redevelopment. Managers will be able to better 

communicate the reasoning behind their selection 

of preferred options if analyses effectively integrate 

ecosystem services and their contributions to human 

well-being. A focus on the ecosystem services that 

matter to the public should also lead to greater public 

understanding of the potential advantages of the options 

for remediation and redevelopment. Finally, performance 

measures defined in terms of contributions to well-being 

that the interested public understands and accepts as 

important should help facilitate communications about 

progress in the remediation and redevelopment process. 

Scientific information can be complex and difficult 

to understand; visual communication approaches 

can help. For example, EPA might use perceptual 

representations (e.g., visualizations of revegetation 

options as viewed from adjacent homes and prominent 

tourist and recreation sites and passageways) to improve 

public understanding of the implications of the various 

restoration and redevelopment alternatives under 

consideration. Consider the restoration plan for the 

Avtex site, which included replanting and encouraging 

re-growth of three different forest types on appropriate 

locations within the site. Accurate visualizations of the 
99

reforestation projects, including their expected growth 

over time, would have been useful for communicating 

the implications of alternative plans. Effectively 

developing and using such visualizations would require 

collaboration between forest ecologists and visualization 

experts (such as landscape architects). These 

collaborations could lead to the creation of accurate 

and realistic representations of how the different forests 

would look from significant viewpoints at different 

stages of the restoration program for each management 

alternative. Psychologists, communications experts, and 

other relevant social or decision scientists might create 

appropriate vehicles and contexts for presenting the 

visualizations to relevant audiences. Computer graphics 

experts might also be helpful. Further interdisciplinary 

collaboration would be required if the visualizations 

were to be accompanied by information about expected 

wildlife or other ecological effects associated with 

each visualized forest condition. While this example 

may seem to be an intricate, exhaustive process, many 

contaminated properties are under redevelopment for 

years (or decades in the case of Superfund projects). 

With proportional resource allocations, this level of 

effort may be appropriate. 

6.3.3.8 Fostering information-sharing about 

ecological valuations at different sites

The committee recommends that EPA pursue the 

broad and rapid transfer of experience within the Agency 

of integrating valuation concepts and techniques into the 

remediation and redevelopment of contaminated sites. 

The Agency can build its capacity to utilize valuation to 

inform local decisions through a systematic exchange of 

information about site-specific valuations. The lessons 

learned from trial efforts, whether successes or failures, 

need to be shared widely across the Agency with the 

regions, program offices, and tool-builders in research 

organizations. The Agency can catalog and share such 

experiences in a number of ways, such as reports, 

databases, or computer-based networks of users sharing 

best practices. The Agency is in the best position to know 

how to take advantage of the knowledge infrastructure 

provided by existing information exchange systems. 

Regardless of how it is done, information should be 

shared broadly.

6.3.4 Summary of recommendations for 

valuation for site-specific decisions

Incorporation of ecological valuation into decisions 

about site remediation and redevelopment can help 

maximize the ecosystem services provided in the 

long run by such sites and the sites’ contributions to 

local well-being. To effectively value the protection 

of ecological systems and services in this context, the 

committee recommends that EPA:

o Provide regional offices with the staff and resources 

needed to incorporate ecological valuation into the 

remediation and redevelopment of contaminated sites.

o Determine the ecosystem services and values 

important to the community and affected parties at 

the beginning of the remediation and redevelopment 

process. 

o Involve the mix of interdisciplinary experts 

appropriate for valuation at different sites.

o Construct conceptual models that include ecosystem 

services.

o Adapt current ecological risk assessment practices 

to include ecological production functions to predict 

effects on relevant ecosystem services.

o Define ecosystem services carefully and develop a 

standard approach for cataloging and accounting 

for ecosystem services for site remediation and 

redevelopment.

o Expand the variety of methods the Agency uses 

to assess the value of services lost or gained from 

current conditions or through proposed Agency 

action.

o Communicate information about ecosystem 

services in discussing options for remediation and 

redevelopment of sites with the public and affected 

parties.

o Create formal systems and processes to foster 

information-sharing about ecological valuations at 

different sites. B
100

7

Conclusion

EPA’s mission to protect human health and the 

environment requires that the Agency understand and 

protect ecosystems and the numerous and varied services 

they provide. Ecosystems play a vital role in our lives, 

providing such services as water purification, flood 

protection, disease regulation, pollination, recreation, 

aesthetic satisfaction, and the control of diseases, pests, 

and climate. EPA’s regulations, programs, and other 

actions, as well as the decisions of other agencies with 

which EPA partners, can affect ecosystem conditions 

and the flow of ecosystem services at a local, regional, 

national, or global scale. To date, however, policy 

analyses have typically focused on only a limited set of 

ecological factors.

Just as policy makers at EPA and elsewhere need 

information about how their actions might affect 

human health in order to make good decisions, they 

also need information about how ecosystems contribute 

to society’s well-being and how contemplated actions 

might affect those contributions. Such information 

can also help inform the public about the need for 

ecosystem protection, the extent to which specific policy 

alternatives address that need, and the value of the 

protection compared to the costs.

7.1 An expanded, integrated valuation 

approach

The committee advises EPA to use an “expanded 

and integrated approach” to ecological valuation. EPA’s 

valuations should be “expanded” by seeking to assess 

and quantify a broader range of values than EPA has 

historically addressed and through a larger suite of 

valuation methods. The valuations should be “integrated” 

by encouraging greater collaboration among a wide 

range of disciplines, including ecologists, economists, 

and other social scientists, at each step of the valuation 

process.

The concept of value is complex. People may use 

many different concepts of value when assessing the 

protection of ecosystems and their services. Values, for 

example, can reflect people’s preferences for alternative 

goods and services (as measured, for example, by 

economic methods, attitude surveys, and decisionscience methods) or potential biophysical concerns (for 

example, biodiversity or energy flows). 

To date, EPA has primarily sought to measure 

economic benefits, as required in many settings by 

statute or executive order. In addition, the Agency’s 

valuation assessments have often focused on those 

ecosystem services or components for which EPA 

has concluded that it could relatively easily measure 

economic benefits, rather than on those services or 

components that may ultimately be most important 

to society. Such a focus can diminish the relevance 

and impact of a value assessment. The committee 

therefore advises the Agency to identify the services and 

components of likely importance to the public at an early 

stage of a valuation and then to focus on characterizing, 

measuring, and assessing the value of the responses of 

those systems and components to EPA’s actions. The 

committee concludes that information based on some of 

the other concepts of value may also be a useful input 

into decisions affecting ecosystems, although members 

of the committee hold different views regarding the 

extent to which specific methods and concepts of 

values should be used in particular policy contexts. The 

methods discussed in this report are at different stages of 

development and validation and are of varying potential 

use depending on the policy context.

EPA should generally seek to measure the values 

that people hold and would express if they were well 

informed about the relevant ecological and human wellbeing factors involved. The committee therefore advises 

EPA to explicitly incorporate that information into the 

valuation process when changes to ecosystems and 

ecosystems services are involved. Valuation surveys, for 

example, should provide relevant ecological information 

to survey respondents, and valuation questions should 

be framed in terms of services or changes that people 

understand and can value. Likewise, deliberative 

processes should convey relevant information to 

participants. The committee also advises EPA to consider 

public education efforts where gaps exist between public 

knowledge and scientific understanding. 

All steps in the valuation process, beginning with 

problem formulation and continuing through the 

characterization, representation, and measurement of 

values, also require information and input from a wide 

variety of disciplines. Instead of ecologists, economists, 

and other social scientists working independently, 

experts should collaborate throughout the process. 

Ecological models need to provide usable inputs for 

valuation, and valuation methods need to address 

important ecological and biophysical effects. 

Of course, EPA conducts ecological valuations within 

a set of institutional, legal, and practical constraints. 

These constraints include substantive directives, 

procedural requirements relating to timing and 

oversight, and resource limitations (both monetary and 

personnel). For example, the preparation of regulatory 
101

impact analyses (RIAs) for proposed regulations 

is subject to OMB oversight and approval. OMB’s 

Circular A-4 makes it clear that RIAs should include an 

economic analysis of the benefits and costs of proposed 

regulations conducted in accordance with the methods 

and procedures of standard welfare economics. At the 

same time, the circular recognizes that it might not be 

possible to monetize all potentially important benefits. In 

such cases, the circular instructs the Agency to quantify 

and report effects in value-relevant biophysical units, 

or, when quantification is not possible, describe the 

effect and associated value qualitatively. Regional and 

site-specific programs and decisions, which are not 

subject to the same legal requirements as national rule 

makings, can offer useful opportunities for testing and 

implementing a broader suite of valuation methods.

The remainder of this chapter summarizes the 

recommendations set out in the earlier chapters of 

this report. Some of these recommendations can 

be implemented in the short run, using the existing 

knowledge base, while others require investments in 

research and data or method development.

7.2 Early identification of how actions 

may contribute to human welfare

As part of an expanded, integrated approach to 

ecological valuation, EPA should identify early in the 

valuation process the ecological responses that are 

likely to be of greatest importance to people, using 

information about ecological importance, human and 

social consequences, and public concerns. EPA should 

then focus its valuation efforts on those responses. This 

will help expand the range of ecological responses that 

EPA characterizes, quantifies, or values. To ensure early 

identification of the ecological responses of most public 

importance, EPA should:

o Begin each valuation by developing a conceptual 

model of the relevant ecosystem and the ecosystem 

services that it generates. This model should serve as 

a road map to guide the valuation.

o Involve staff throughout EPA, as well as outside 

experts in the biophysical and social sciences, in 

constructing the conceptual model. EPA should also 

seek information about relevant public concerns 

and needs.

o Incorporate new information into the model, in an 

iterative process, as the value assessment proceeds.

7.3 Prediction of ecological responses 

in value-relevant terms

Another important aspect of an expanded, integrated 

approach to ecological valuation is that the Agency 

should predict ecological responses to governmental 

actions in terms that are relevant to valuation. 

Prediction of ecological responses is a key step in 

valuation efforts. To predict responses in value-relevant 

terms, EPA should focus on the effects of decisions on 

ecosystem services or other ecological features that are 

of most concern to people. This in turn will require the 

Agency to go beyond predicting only the biophysical 

effects of decisions and to map those effects to 

responses in ecosystem services or components that the 

public values. 

Unfortunately, the science needed to do this has 

been limited, presenting a barrier to effective valuation 

of ecological systems and services. To better estimate 

ecological responses in value-relevant terms in the 

future, EPA should:

o Identify and develop measures of ecosystem services 

that are relevant to and directly useful for valuation. 

This will require increased interaction within EPA 

between natural and social scientists. In identifying 

and assessing the value of services, EPA should 

describe them in terms that are meaningful and 

understandable to the public.

o Where possible, use ecological production functions 

to estimate how effects on the structure and function 

of ecosystems, resulting from the actions of EPA 

or partnering agencies, will affect the provision of 

ecosystem services for which values can then be 

estimated.

o Where complete ecological production functions do 

not exist,

• Examine available ecological indicators that are 

correlated with changes in ecosystem services 
102

to provide information about the effects of 

governmental actions on those services.

• Use methods such as meta-analysis that can 

provide general information about key ecological 

relationships important in the valuation.

o Support all ecological valuations by ecological 

models and data sufficient to understand and 

estimate the likely ecological responses to the major 

alternatives being considered by decision makers.

7.4 Valuation

Central to an expanded, integrated valuation 

approach is the need to carefully characterize and, when 

possible, quantify and value the responses in ecosystem 

services or components. Three steps may be useful in 

this regard. First, EPA should consider the appropriate 

use of a broader suite of valuation methods than it has 

historically employed. As summarized in Table 3 at 

pages 42-43, the Committee looked at the possible use 

of not only economic methods, but also such alternative 

methods as measures of attitudes, preferences, and 

intentions; civic valuation; decision science approaches; 

ecosystem benefit indicators, biophysical ranking 

methods; and cost as a proxy for value. An expanded 

suite of valuation methods could allow EPA to better 

capture the full range of contributions stemming from 

ecosystem protection and the multiple sources of value 

derived from ecosystems – although it is important to 

recognize that different methods may measure different 

things and thus not be directly additive or comparable. 

Even when the Agency is required or chooses to base 

its assessment on economic benefits, other valuation 

methods may be useful in supporting, extending, and 

improving the basis and rationale for Agency decisions.

In considering what methods to use in specific 

contexts, EPA should keep in mind that many Agency 

actions affect not only ecosystems and ecosystem 

services but also other things that contribute to human 

well-being – e.g., human health. In these cases, 

valuation methods that focus solely on ecological 

effects will necessarily provide an incomplete picture 

of the consequences of EPA’s actions, and the Agency 

should ensure that it uses valuation methods that capture 

information on the widest possible range of effects of 

Agency actions.

To move toward the possible use of a broader suite of 

valuation methods, EPA should:

o Pilot and evaluate the use of alternative methods 

where legally permissible and scientifically 

appropriate. 

o Develop criteria to determine the suitability of 

alternative methods for use in specific decision 

contexts. Given differences in premises, goals, 

concerns, and external constraints, appropriate uses 

will vary among methods and contexts. As discussed, 

different methods are also at different stages of 

development and validation.

EPA also should more carefully evaluate the 

appropriate use of value transfers. EPA should identify 

relevant criteria for determining the appropriateness 

of value transfers. These criteria should consider 

similarities and differences in societal preferences 

and the nature of the biophysical systems between 

the study site and the policy site. Using these criteria, 

EPA analysts and those providing oversight should 

flag problematic transfers and clarify assumptions and 

limitations of the study-site results.

7.5 Other cross-cutting issues

7.5.1 Deliberative processes

Deliberative processes, in which analysts, decision 

makers, and/or members of the public meet in facilitated 

interaction, can be potentially useful in several steps 

of the valuation process. The committee particularly 

recommends that EPA consider using carefullyconducted deliberative processes to provide information 

about what people care about – especially where the 

public may not be fully informed about ecosystem 

services. Where EPA uses deliberative processes, it 

should provide the processes with the financial and staff 

resources needed to adequately address and incorporate 

relevant science and best practices.

7.5.2 Uncertainty

Because an understanding of the uncertainties 

underlying all aspects of ecological valuation will 

enable more informed policy making, the committee 

recommends that EPA more fully characterize and 

communicate uncertainty. In this regard, EPA should 

o Go beyond simple sensitivity analysis in assessing 

uncertainty, and make greater use of approaches, such 

as Monte Carlo analysis, that provide more useful 

and appropriate characterizations of uncertainty in 

complex contexts such as ecological valuation. 

o Provide information to decision makers and the 

public about the level of uncertainty involved in 

ecological valuation efforts. EPA should not relegate 

uncertainty analyses to appendices but should 

ensure that a summary of uncertainty is given as 

much prominence as the valuation estimate itself, 

with careful attention to how recipients are likely 

to understand the uncertainties. EPA should also 

explain qualitatively any limitations in the uncertainty 

analysis.

While EPA should improve its characterization 

and reporting of uncertainty, the mere existence of 

uncertainty should not be an excuse for delaying actions 

where the benefits of immediate action outweigh the 

value of attempting to further reduce the uncertainty. 

Some uncertainty will always exist.
103

7.5.3 Communication of valuation information

The success of ecological valuations also depends 

on how EPA communicates ecological valuation 

information to decision makers and the public. To 

promote effective communications, the committee 

recommends that EPA design communications that are 

responsive to the needs of the users of the valuation 

information and follow basic guidelines for risk and 

technical communications. EPA’s Risk Characterization 

Handbook provides one set of useful guidelines, 

including transparency, clarity, consistency, and 

reasonableness. To the extent feasible, EPA should 

communicate not only value information but also 

information about the nature, status, and changes to the 

ecological systems and services.

7.6 Context-specific recommendations

The use of an expanded, integrated approach can 

improve ecological valuation in multiple settings. 

Valuation of ecological systems and services, for 

example, is critical in national rule makings, where 

executive orders often require cost-benefit analyses 

and several statutes require weighing of economic 

benefits and costs. Regional EPA offices can find 

valuation important in setting program priorities and 

in assisting other governmental and non-governmental 

organizations in choosing among environmental options 

and communicating the importance of their actions to 

the public. Finally, ecological valuation can help EPA to 

enhance the cleanup of hazardous waste sites and make 

other site-specific decisions.

7.6.1 National rule making

Applying an expanded and integrated valuation 

approach to national rule making will entail some 

challenges but offers important opportunities for 

improvement as well. EPA can implement some, but 

not all, of the committee’s recommendations using the 

existing knowledge base. The committee also recognizes 

that EPA must conduct valuations for national rule 

making in compliance with statutory and executive 

mandates. In the short run, EPA can take several actions 

to improve valuations for national rule making:

o EPA should develop a conceptual model at the 

beginning of each valuation, as discussed above, 

to serve as a guide or road map. To ensure that 

the model captures the ecological properties and 

services that are potentially important to people, 

EPA should incorporate input both from relevant 

science and about public preferences and concerns. 

EPA can identify public concerns through a variety 

of methods, drawing on either existing knowledge or 

interactive processes designed to elicit public input. 

o The Agency should address site-specific variability 

in the impact of a rule by producing case 

studies for important ecosystem types and then 

aggregating across the studies where information is 

available about the joint distribution of ecosystem 

characteristics and human populations affected 

by them.

o EPA should not compromise the quality of its 

valuations by inappropriately applying value 

transfers. Where the values of ecosystem services 

are primarily local, the Agency can rely on scientifically-sound value transfers using prior valuations at 

the local level. However, for services valued more 

broadly, EPA should draw from studies with broad 

geographical coverage (in terms of both the changes 

that are valued and the population whose values 

are assessed).

o EPA should pilot and evaluate the use of a broader 

suite of valuation methods to support and improve 

RIAs. Although OMB Circular A-4 requires RIAs 

to monetize benefits to the extent possible using 

economic valuation methods, other methods could be 

useful in the following ways: 

	 • Helping to identify early in the process the

ecosystem services that are likely to be of concern 

to the public and that should therefore be the focus 

of the benefit-cost analysis

	 • Addressing the requirement in Circular A-4 to

provide quantitative or qualitative information 

about the possible magnitude of benefits (and 

costs) when they cannot be monetized using 

economic valuation

	 • Providing supplemental information outside the

formal benefit-cost analysis about sources and 

concepts of value that might be of interest to EPA 

and the public but not fully reflected in economic 

benefits. 

o To ensure that RIAs do not inappropriately focus 

only on impacts that have been monetized, EPA 

should also report on other ecological impacts in 

appropriate units where possible, as required by 

Circular A-4. The Agency should label aggregate 

monetized economic benefits as “total economic 

benefits that can be monetized,” not as “total 

benefits.”

o EPA should include a separate chapter on uncertainty 

characterization in each RIA or value assessment.

7.6.2 Regional partnerships

The committee sees great potential in undertaking a 

comprehensive and systematic approach to estimating the 

value of protecting ecosystems and services at a regional 

scale, in part because of the effectiveness with which 

EPA regional offices can partner with other agencies and 

state and local governments. Regional-scale analyses hold 

great potential to inform decision makers and the public 

about the value of protecting ecosystems and services, but 

this potential is at present largely unrealized. The general 
104

recommendations of this report provide a guide for 

regional valuations. Regional valuations are a particularly 

appropriate setting in which to test alternative valuation 

methods because there are generally fewer legal or 

regulatory restrictions on what methods can be used. 

In addition to recommending that regional offices adopt 

the general recommendations of this report in conducting 

ecological valuations, the committee advises EPA to:

o Encourage its regions to engage in valuation efforts to 

support decision making both by the regions and by 

partnering governmental agencies.

o Provide adequate resources to EPA regional staff 

to develop the expertise needed to undertake 

comprehensive and systematic studies of the value of 

protecting ecosystems and services.

o Ensure that regions can learn from valuation efforts 

by other regions. EPA regional offices should 

document valuation efforts and share them with 

other regional offices, EPA’s National Center for 

Environmental Economics, and EPA’s Office of 

Research and Development.

7.6.3.Site-specific decisions

Incorporation of ecological valuation into local 

decisions about the remediation and redevelopment 

of contaminated sites can help enhance the ecosystem 

services provided by such sites in the long run and thus 

the sites’ contributions to local well-being. The general 

recommendations of the report again provide a useful 

guide for such site-specific valuations. The committee 

also advises the Agency to:

o Provide regional offices with the staff and resources 

needed to effectively incorporate ecological 

valuation into the remediation and redevelopment of 

contaminated sites.

o Determine the ecosystem services and values 

important to the community and affected parties 

at the beginning of the remediation and 

redevelopment process.

o Adapt current ecological risk assessment practices 

to incorporate ecological production functions and 

predict the effects of remediation and redevelopment 

options on ecosystem services.

o Communicate information about ecosystem 

services in discussing options for remediation and 

redevelopment with the public and affected parties.

o Create formal systems and processes to foster 

information-sharing about ecological valuations at 

different sites.

7.7 Recommendations for research and 

data sharing

EPA should use its research programs to provide the 

ecological information needed for valuation, develop 

and test valuation methods, and share data. As an overarching recommendation, the report advises EPA to more 

closely coordinate its research programs on the valuation 

of ecosystem services and to develop links with other 

governmental agencies and organizations engaged in 

valuation and valuation research. It advises, at a more 

general level, fostering greater interaction between 

natural scientists and social scientists in identifying 

relevant ecosystem services and developing and implementing processes for measuring and estimating 

their value. Although the committee has identified those 

research areas that it believes are important in advancing 

EPA’s ability to conduct valuations of ecological systems 

and services, the committee has not attempted to rank 

or prioritize among all of its research recommendations. 

EPA should develop a research strategy, building on the 

recommendations in this report, that identifies “lowhanging fruit” and prioritizes studies that are likely 

to have the largest payoff in both advancing valuation 

methods and providing valuation information of 

importance to EPA in its work.

To develop EPA’s ability to determine and quantify 

ecological responses to governmental decisions, the 

Agency should:

o Support the development of quantitative ecosystem 

models and baseline data on ecological stressors 

and ecosystem service flows that can support 

valuation efforts at the local, regional, national, and 

global levels.

o Promote efforts to collect data that can be used to 

parameterize ecological models for site-specific 

analysis and case studies or that can be transferred or 

scaled to other contexts.

o Carefully plan and actively pursue research to 

develop and generate ecological production functions 

for valuation, including Office of Research and 

Development and STAR research on ecological 

services and support for modeling and methods 

development. The committee believes that this is a 

research area of high priority.

o Given the complexity of developing and using 

complete ecological production functions, continue 

and accelerate research to develop key indicators 

for use in ecological valuation. Such indicators 

should meet ecological and social science criteria for 

effectively simplifying and synthesizing underlying 

complexity and link to an effective monitoring and 

reporting program.

To develop EPA’s capabilities for estimating the value 

of ecological responses to governmental decisions, EPA 

should:

o Support new studies and the development of new 

methodologies that will enhance the future use of 

ecological value transfers, particularly at the national 
105

level. Such research should include national surveys 

related to ecosystem services with broad (rather than 

localized) implications so that value estimates might 

be usable in multiple rule-making contexts.

o Invest in research designed to reduce uncertainties 

associated with ecological valuation through data 

collection, improvements in measurement, theory 

building, and theory validation. 

o Incorporate the research needs of regional offices for 

systematic valuation studies in future calls by EPA for 

extramural ecological valuation research proposals. 

To access and share information to enhance the 

Agency’s capabilities for ecological valuation, 

EPA should:

o Work with other federal agencies and scientific 

organizations such as the National Science 

Foundation to encourage the sharing of ecological 

data and the development of more consistent 

ecological measures that are useful for valuation 

purposes. A number of governmental organizations, 

such as the United States Department of Agriculture 

and the Fish & Wildlife Service, are working on 

biophysical modeling and valuation, and EPA could 

usefully partner with them.

o Support efforts to develop Web-based databases of 

existing valuation studies that could be used in value 

transfers. The databases should include valuation 

studies across a range of ecosystems and ecosystem 

services. The databases should also carefully describe 

the characteristics and assumptions of each study, 

in order to increase the likelihood that those studies 

most comparable to new valuations can be identified 

for use. 

o Support the development of national-level databases 

of information useful in the development of new 

valuation studies. Such information should include 

data on the joint distribution of ecosystem and 

human population characteristics that are important 

determinants of the value of ecosystem services.

o Develop processes and information resources so 

that EPA staff in one region or office of the Agency 

can learn effectively from valuation efforts being 

undertaken elsewhere within the Agency. B
106

The SAB Web site provides three sets of materials 

that supplement this report:

1. More detailed information on methods potentially 

useful for ecological valuation, as described in 

chapter 4 of this report. 

2. A discussion of survey issues relevant to ecological 

valuation, including current best practices and 

recommendations for research 

3. A summary of an SAB 2005 workshop on “Science 

for valuation of EPA’s ecological protection decisions 

and programs.”

These materials do not represent the consensus 

views of the committee, nor have they been reviewed 

and approved by the chartered Science Advisory Board. 

They are provided to extend the discussion of methods 

in chapter 4 of the main report and to encourage 

further deliberation within EPA and the broader 

scientific community about how to meet the need for 

an integrated and expanded approach for valuing the 

protection of ecological systems and services.

Methods potentially useful for 

ecological valuation

The SAB Web site provides descriptions of methods 

and approaches prepared by members of the C-VPESS 

as resources for the committee and others interested 

in ecological valuation (http://yosemite.epa.gov/sab/

sabproduct.nsf/WebBOARD/C-VPESS_Web_Methods_

Draft?OpenDocument). Methods are described with 

specific reference to how they might be used by the EPA 

for valuing the protection of ecological systems and 

services within the valuation approach recommended by 

the committee. Some of the methods have already been 

used extensively in EPA policy and decision making. 

Some appear never or only rarely to have been used by 

the Agency, but are widely used by other agencies. Some 

are less proven in policy making contexts and should be 

considered experimental. All of the methods described have 

both conceptual and practical strengths and limitations.

The descriptions of these methods and approaches 

and of their utility for ecological valuation at EPA do 

not represent the consensus views of the committee, nor 

have they been reviewed and approved by the chartered 

Science Advisory Board. They are offered to extend 

and elaborate the very brief descriptions provided in 

chapter 4 of the main report and to encourage further 

deliberation within EPA and the broader scientific 

community about how to meet the need for an integrated 

and expanded approach for valuing the protection of 

ecological systems and services. 

The descriptions provide suggestions for further 

reading, potential applications of the methods, and future 

research opportunities. The descriptions of specific 

methods and approaches are supplemented by a separate 

Web-accessible discussion (http://yosemite.epa.gov/Sab/

Sabproduct.nsf/WebFiles/SurveyMethods/$File/Survey_

methods.pdf) of the use of survey techniques employed in 

some valuation methods.

Members of the C-VPESS do agree that EPA should 

carefully characterize and, when possible, quantify and 

value the responses in ecosystem services or components. 

They agree that a wider range of valuation methods 

can play a potential role throughout the expanded and 

integrated valuation process the committee envisions.

An expanded suite of valuation methods could allow 

EPA to better capture the full range of contributions 

stemming from ecosystem protection and the multiple 

types of value derived from ecosystems. At the same 

time, it is important to recognize that different methods 

may measure different values and thus not be additive or 

comparable. Even when the Agency is required or chooses 

to base its valuation assessment on economic values, 

however, use of additional methods may be useful in 

supporting, improving, or extending the valuation.

The descriptions of methods and approaches 

generally include the following kinds of information:

o Brief description of the method

o Status of the method

o Conceptual and practical strengths and limitations

o Treatment of uncertainty

o Research needs

o Key references

Methods and approaches described include:

o Measures of attitudes, preferences, and intentions

• Surveys of attitudes, preferences, and intentions

• Focus groups

• Individual narratives

 Mental model approaches

	 • Emerging methods

o Economic methods

• Market-based methods

Appendix A: Web-accessible materials 

on ecological valuation developed by or 

for the C-VPESS
107

• Non-market methods – revealed preference

  Travel cost

  Hedonics

  Averting behavior models

• Non-market methods – stated preference

• Combining revealed and stated preference methods

o Civic valuation

• Referenda and initiatives

• Citizen valuation juries

o Decision science methods

o Ecosystem benefit indicators

o Biophysical ranking methods

• Conservation value method

• Rankings based on energy and material flows

o Methods using cost as a proxy for value

• Replacement costs

• Tradable permits

• Habitat equivalency analysis

o Deliberative processes

• Mediated modeling

• Constructed value approaches

Survey issues for ecological valuation: 

Current best practices and recommendations 

for research

This document provides an introduction for EPA 

staff to questions posed to the C-VPESS pertaining 

to survey use for ecological valuation. It gives an 

overview of how recent research and evolving practice 

relating to those questions might assist the Agency. 

The document provides a definition of survey research, 

discusses survey design, identifies elements of a 

well-designed survey, addresses assessment of survey 

accuracy, and discusses challenges in using surveys for 

ecosystem protection valuation. The document can be 

found at the SAB Web site at: http://yosemite.epa.gov/

Sab/Sabproduct.nsf/WebFiles/SurveyMethods/$File/

Survey_methods.pdf.

Science Advisory Board workshop summary: 

Science for valuation of EPA’s ecological 

protection decisions and programs. Summary 

of workshop held December 13-14, 2005, 

Washington, DC

This document summarizes a public workshop held 

on December 13-14, 2005, in Washington, D.C., on 

“Science for valuation of EPA’s ecological protection 

decisions and programs.” The purpose of the workshop 

was to discuss the initial work of the SAB’s C-VPESS; 

to provide an opportunity for members of the SAB, the 

Advisory Council on Clean Air Compliance Analysis, 

and Clean Air Scientific Advisory Committee to learn 

from each others’ work relating to ecological valuation; 

and to feature feedback and insights from Agency 

clients and outside subject matter experts. The agenda 

included presentations and discussions with advisory 

committee members, Agency personnel, and invited 

speakers. . The workshop summary can be found on 

the SAB Web site at: http://yosemite.epa.gov/Sab/

Sabproduct.nsf/WebFiles/EcoWorkshop/$File/sab_

wksp_summary_12_13-14_05.pdf.

AMD Acid mine drainage

BTF Benefit transfer 

CAFO Concentrated animal feeding operation

CERCLA Comprehensive Environmental Response, 

Compensation, and Liability Act

C-VPESS Committee on Valuing the Protection of 

Ecological Systems and Services

EVRI Environmental Valuation Reference 

Inventory

FPD Forest Preserve District

GEAE Generic ecological assessment endpoints

GDP Gross domestic product

GIS Geographic Information System 

GPRA Government Performance and Results Act

HEA Habitat equivalency analysis

LTER Long-term Ecological Research

NCEE National Center for Environmental 

Economics

NEBA Net Environmental Benefit Assessment

NPL National Priorities List

NRC National Research Council

NRDA Natural Resource Damage Assessments

NSF National Science Foundation

OMB Office of Management and Budget

RIA Regulatory Impact Analysis

STAR Science to Achieve Results

VOC Volatile organic compound

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1. Laws include: the Clean Air Act, Clean Water Act, 

Comprehensive Environmental Response, Compensation, 

and Liability Act, Federal Insecticide, Fungicide and 

Rodenticide Act, Toxic Substances Control Act, and 

Resource Conservation and Recovery Act.

2. Although C-VPESS was initiated by the SAB, senior 

EPA managers supported the concept of this SAB project 

and participated in the initial background workshop that 

launched the work of the C-VPESS. 

3. The SAB Staff Office published a Federal Register notice 

on March 7, 2003, (68 FR 11082-11084) announcing the 

project and calling for the public to nominate experts in 

the following areas: decision science, ecology, economics, 

engineering, law, philosophy, political science, and 

psychology with emphasis in ecosystem protection. The 

SAB Staff Office published a memorandum on August 11, 

2003, documenting the steps involved in forming the new 

committee and finalizing its membership.

4. The committee developed the conclusions in this report after 

multiple public meetings, teleconferences and workshops 

including: (a) an Initial Background Workshop on October 

27, 2003, to learn the range of EPA’s needs for science-based 

information on valuing the protection of ecological systems 

and services from managers of EPA Headquarters and 

Regional Offices; (b) a Workshop on Different Approaches 

and Methods for Valuing the Protection of Ecological 

Systems and Services, held on April 13-14, 2004; (c) an 

advisory meeting focused on support documents for national 

rule makings held on June 14-15, 2004; (d) an advisory 

meeting focused on regional science needs, in EPA’s Region 

9 (San Francisco) Office on Sept. 13, 14, and 15, 2004; (e) 

advisory meetings held on January 25-26, 2005, and April 

12-13, 2005, to review EPA’s draft Ecological Benefits 

Assessment Strategic Plan; and (f) a Workshop on Science 

for Valuation of EPA’s Ecological Protection Decisions and 

Programs, held on December 13-14, 2005, to discuss the 

integrated and expanded approach described in this paper. 

The committee also discussed text drafted for this report at 

public meetings on October 25, 2005; May 9, 2006; October 

5-6, 2006, and May 1-2, 2007, and on ten subsequent public 

teleconferences. 

5. The committee also notes a report published shortly before 

this report was finalized (United Kingdom Department for 

Environment, Food and Rural Affairs, 2007). 

6. Likewise, this definition would not include goods or 

services such as recreation that are produced by combining 

ecological inputs or outputs with conventional inputs (such 

as labor, capital, or time). In addition, Boyd and Banzhaf 

(2006) advocate defining changes in ecosystem services in 

terms of standardized units or quantities, which requires 

that they be measurable in practice. Such an approach is 

consistent with the concept of “green accounting,” which 

extends the principles embodied in measuring marketed 

products to the measurement and consideration of the 

production, or changes in the stock, of ecological or other 

environmental “products” (Nordaus and Kokkelenberg, 

1999). 

7. Even the term “values” itself means very different things 

within different disciplines. For example, economists 

associate values with changes, while other disciplines 

associate values with beliefs or mental structures that 

influence behavior or provide a “moral compass.” For 

discussions of the concepts of value used within different 

disciplines, see Dietz et al., 2005; Fischoff, 1991, 2005; 

and Hitlin and Piliavin, 2004.

8. There is controversy over the meaning of intrinsic value 

(Korsgaard, 1996). Many people take intrinsic value to 

mean that the value of something is inherent in that thing. 

Some philosophers have argued that value or goodness is 

a simple non-natural property of things (see Moore, 1903 

for the classical statement of this position), and others have 

argued that value or goodness is not a simple property of 

things but one that supervenes on the natural properties to 

which we appeal to explain a thing’s goodness. This view 

is defended by, among others, contemporary moral realists; 

see McDowell (1985), Sturgeon (1985), Sayre-McCord 

(1988), and Brink (1989).

9. Although table 1 lists concepts of value considered by 

the committee, these value concepts are not mutually 

exclusive. For example, values expressing attitudes or 

judgments can be based on the same utilitarian goals 

as those underlying economic values or on the same 

considerations that underlie civic values. Likewise, 

constructed preferences can relate to self-interested 

attitudes or judgments (as economic values do) as well as 

expressed civic values.

10. Some members of the committee argued that in a broader 

definition, “economic” should refer to all methods of 

assessing tradeoffs and contributions to human well-being, 

not just those based on willingness to pay or willingness to 

accept. However, in this report, “economic values” include 

only values reflecting preference-based tradeoffs.

11. Monetized measures of economic output form the basis 

of national income accounts. While historically these 

have included only marketed outputs (such as agriculture 

and manufacturing), in principle the contributions of 

ecosystems and other natural assets to national income 

or aggregate output could be defined. A number of 

researchers have examined efforts to expand the national 

accounts to include these types of contributions (Nordhaus 

and Kokkelenberg, 1999). In the context of national 

income accounts, “value” is typically defined in terms 

of the dollar value of output, computed using prices and 

quantities. However, given the committee’s focus on 

valuing changes resulting from EPA decisions or actions, 

this report defines economic values in terms of tradeoffs, 

consistent with standard welfare economics. 

12. See, for example, Seidl (2002) for a survey of the preference 

reversal literature.

13. Environmental values are often defined in terms of a set of 

guiding principles, concepts or beliefs that guide decisions 

and evaluations. For a recent survey on environmental 

values, see Dietz et al. (2005). 

14. Under GPRA, the Office of Management and Budget 

requires EPA to periodically identify its strategic goals and 

describe both the social costs and budget costs associated 

with them. EPA’s strategic plan for 2003-2008 described the 

current social costs and willingness-to-pay or willingnessto-accept analyses of EPA’s programs and policies under 

each strategic goal area for the year 2002 (EPA, 2003). 

Endnotes
118

This analysis repeatedly points out that EPA lacks data and 

methods to quantify willingness-to-pay or willingnessto-accept associated with the goals in its strategic plan. In 

addition, GPRA established requirements for assessing the 

effectiveness of federal programs, including the outcomes of 

programs intended to protect ecological resources. EPA must 

report annually on its progress in meeting program objectives 

linked to strategic plan goals and must engage periodically 

in an in-depth review [through the Program Assessment 

Rating Tool (PART)] of selected programs to identify their 

net contributions to human welfare and to evaluate their 

effectiveness in delivering meaningful, ambitious program 

outcomes. Characterizing ecological contributions to human 

welfare associated with EPA programs is a necessary part of 

the program assessment process.

15. These interviews were conducted by one committee 

member, Dr. James Boyd, in conjunction with the 

Designated Federal Officer Dr. Angela Nugent, over the 

period September 22, 2004, through November 23, 2005. 

In seven sets of interviews, Dr. Boyd spoke with staff from 

the Office of Policy, Economics and Innovation, Office of 

Water, Office of Air and Radiation, and the Office of Solid 

Waste and Emergency Response. 

16. NCEE is typically brought in by the program offices to 

help both design and review RIAs. NCEE can be thought 

to provide a centralized “screening” function for rules 

and analysis before they go to OMB. NCEE is actively 

involved in discussions with OMB as rules and supporting 

analysis are developed and advanced. 

17. In addition, Circular A-4 states (p. 27) “If monetization 

is impossible, explain why and present all available 

quantitative information” and “If you are not able to 

quantify the effects, you should present any relevant 

quantitative information along with a description of the 

unquantified effects, such as ecological gains, improvements 

in quality of life, and aesthetic beauty” (p. 26).

18. The committee reviewed and critically evaluated the CAFO 

Environmental and Economic Benefits Analysis at its June 

15, 2004, meeting. As stated in the Background Document 

for SAB Committee on Valuing the Protection of Ecological 

Systems and Services for its session on June 15, 2004, the 

purpose of this exercise was “to provide a vehicle to help 

the Committee identify approaches, methods, and data for 

characterizing the full suite of ecological values’ affected by 

key types of Agency actions and appropriate assumptions 

regarding those approaches, methods, and data for these 

types of decisions.” The committee based its review on 

EPA’s final benefits report (EPA, 2002b) and a briefing 

provided by the EPA Office of Water staff. 

19. In December 2000, EPA proposed a new CAFO rule 

under the federal Clean Water Act to replace 25-year-old 

technology requirements and permit regulations (66 FR 

2959). EPA published its final rule in December 2003 

(68 FR 7176). The new CAFO regulations, which cover 

over 15,000 large CAFO operations, reduce manure and 

wastewater pollutants from feedlots and land applications 

of manure and remove exemptions for stormwater-only 

discharges.

20. The potential “use” benefits included in-stream uses 

(commercial fisheries, navigation, recreation, subsistence, 

and human health risk), near-stream uses (non-contact 

recreation, such as camping, and nonconsumptive, such as 

wildlife viewing), off-stream consumptive uses (drinking 

water, agricultural/irrigation uses, and industrial/commercial 

uses), aesthetic value (for people residing, working, or 

traveling near water), and the option value of future services. 

The potential “non-use” values included ecological values 

(reduced mortality/morbidity of certain species, improved 

reproductive success, increased diversity, and improved 

habitat/sustainability), bequest values, and existence values.

21. These benefits were recreational use and non-use of 

affected waterways, protection of drinking water wells, 

protection of animal water supplies, avoidance of public 

water treatment, improved shellfish harvest, improved 

recreational fishing in estuaries, and reduced fish kills.

22. These include reduced eutrophication of estuaries; reduced 

pathogen contamination of drinking water supplies; 

reduced human and ecological risks from hormones, 

antibiotics, metals, and salts; improved soil properties from 

reduced over-application of manure; and “other benefits”.

23. EPA apparently conducted no new economic valuation 

studies (although a limited amount of new ecological 

research was conducted) and did not consider the possible 

benefits of developing new information where important 

benefits could not be valued in monetary terms based on 

existing data. 

24. For example, while the report notes the potential effects 

of discharging hormones and other pharmaceuticals 

commonly used in CAFOs into drinking water sources 

and aquatic ecosystems, the nature and possible ecological 

significance of these effects is not adequately developed 

or presented. Similarly, the report does not adequately 

address the well-known consequences of discharging 

trihalomethane precursors into drinking-water sources.

25. EPA used estimates based on a variety of public surveys 

in its benefit transfer efforts, including: a national survey 

(1983) that determined individuals’ willingness to pay for 

changes in surface water quality relating to water-based 

recreational activities (section 4 of the CAFO Report); a 

series of surveys (1992, 1995, 1997) of willingness to pay 

for reduced/avoided nitrate (or unspecified) contamination 

of drinking water supplies (section 7); and several studies 

(1988, 1995) of recreational fishers’ values (travel cost, 

random utility model) for improved/protected fishing 

success related to nitrate pollution levels in a North 

Carolina estuary (section 9). 

26. Although EPA later prepared more detailed conceptual 

models of the CAFO rule’s impact on various ecological 

systems and services, EPA did not prepare these models 

until after the Agency finished its analysis. 

27. Contamination of estuaries, for example, might negatively 

affect fisheries in the estuary (a primary effect) but might 

have an even greater impact on offshore fisheries that have 

their nurseries in the estuary (a secondary effect). 

28. The goal of EPA’s analysis was a national-level 

assessment of the effects of the CAFO rule. This 

involved the effects of approximately 15,000 individual 

facilities, each contributing pollutants across local 

watersheds into local and regional aquatic ecosystems. 

A few intensive case studies were mentioned in 

the report and used to calibrate the national scale 

models (e.g., NWPCAM, GLEAMS), but there was 

no indication that these more intensive data sets were 

strategically selected or used systematically for formal 

sensitivity tests or validations of the national-scale 

model results.

29. This could include either a robust public involvement process 

following Administrative Procedures Act requirements (e.g., 

publication in the Federal Register), or some other public 

involvement process (see EPA’s public involvement policy 

[EPA Office of Policy, Economics and Innovation, 2003] and 

the SAB report on science and stakeholder involvement [EPA 

Science Advisory Board, 2001]). 
119

30. In theory, one can value a final product either directly 

(output valuation) or indirectly as the sum of the derived 

value of the inputs (input valuation), but not both, because 

separately valuing both intermediate and final products 

leads to double counting. In some cases, it may be easier 

or more appropriate to value the intermediate service, 

while in other cases the change in the final product can be 

directly valued.

31. Indicators therefore provide information on the direction 

and possible magnitude of the impact or response of an 

ecosystem to a stressor, rather than on merely the stressor 

itself.

32. Note that these essential ecosystem characteristics are very 

similar to the seven ecological indicators in EPA’s report on 

assessing ecological systems (EPA Science Advisory Board 

2002b): landscape condition, biotic condition, chemical and 

physical characteristics, ecological processes, hydrology and 

geomorphology and natural disturbance regimes.

33. The NSF has recently emphasized engaging social 

sciences in LTER, increasing the potential usefulness of 

LTER in building EPA’s capacity for ecological valuations. 

Although most LTERs are in pristine areas, two urban sites 

and an agricultural site could be of special value to the 

Agency.

34. These supplemental materials were compiled by the 

committee as background information, but they do not 

necessarily represent the consensus views of the committee, 

nor have they been reviewed and approved by the chartered 

Science Advisory Board (see appendix A for more detail).

35. The U.S. federal government is one of the largest 

producers of survey data, which form the basis of many 

government policy making decisions (see the table on page 

120.). 

36. This comparison of causal beliefs with formal decision 

models entails three steps. First is the construction of 

an expert decision model, generally through systematic, 

formal decision analysis involving scientists and other 

topical experts, individually or in groups. Following this is 

the analysis of semi-structured interviews with individuals 

from the population of interest, and comparison of these 

to the decision model. Third is the design and fielding of a 

survey to test the reliability of findings from the interviews 

in a representative sample of the population of interest or 

the public at large. The interviews and surveys employ 

mixed methods, and assess both how decision makers 

intuitively structure and conceptualize their environmental 

mitigation decisions, as well as how they react to 

structured stimuli and questions (Morgan et al., 2002). 

37. The discussion here deals with indicators that are based on 

a narrowly-defined objective. More generally, a number 

of “sustainability indicators” have been developed, which 

aggregate measures reflecting a variety of factors deemed 

relevant to this broad goal. See Parris and Kates (2003) for 

a discussion of sustainability indicators and the challenges 

that arise in their use. 

38. Both embodied energy analysis and ecological footprint 

analysis use a consistent set of accounting principles 

based on input-output analysis to compute these costs. 

An alternative biophysical method, emergy, on the other 

hand, also seeks to measure the energy cost of producing 

a good or service, but it does not follow these principles, 

and hence, does not generally satisfy basic adding-up 

properties. Rather, it focuses on converting inputs of 

varying quality to a common energy metric – usually solar 

energy equivalents – so that they can be combined into a 

cost estimate measured in those units.

39. People using models may sometimes find that the implications 

of their models are surprising and unacceptable to them. For 

example, Slovic et al. (1982) found that people preferred a 

convex function (their general model) to express the value of 

varying numbers of lives lost, yet made choices in violation 

of this abstract model. They had not realized that the abstract 

model implied choices that were unacceptable to them. In the 

view of Slovic and others, modeling needs to be interactive 

and mixed with examples of the model’s specific implications.

40. While stakeholder processes are sometimes used as a 

decision mechanism per se, the C-VPESS considered 

them only as a way of providing informed input from 

the public into valuation processes. A 2001 SAB report 

assessed stakeholder processes involving environmental 

science and concluded that they are appropriate as a 

decision making mechanism per se in only a modest 

subset of environmental regulatory decisions under select 

conditions, if at all (SAB, 2001).

41. Valuations also require a variety of other predictions, 

including predicting the anthropogenic response to EPA 

actions or decisions. Valuations sometimes ignore the need 

for such predictions. For example, many valuations assume 

that the regulated community will comply fully with 

regulations and not adjust other behavior in response to 

the regulation. In many cases, this assumption is incorrect. 

Where valuations do incorporate additional predictions, 

however, they again are subject to uncertainty.

42. For a more detailed discussion of the sources and possible 

typologies of uncertainty, see Krupnick, Morgenstern et al. 

(2006).

43. Depending on the context, explicit reporting of 

uncertainties may be perceived as indicating dishonesty 

or incompetence (Johnson, 2003; Johnson and Slovic, 

1995, 1998) and are sometimes treated in public policy 

discussions as indicating junk science (e.g., Freudenberg 

et al., 2008). Despite these perceptions, it is important 

to convey that uncertainties are inherent in all science 

and that good science acknowledges the remaining 

uncertainties. Experts communicating uncertainty to policy 

makers or the public should beware of unintended effects 

and design and test their communications accordingly. 

44. The discussion of value in the National Research Council 

report (2001) and SAB review of the EPA’s Draft Report 

on the Environment (EPA SAB, 2005) and related 

literature (e.g., Failing and Gregory, 2003) tends to focus 

more on qualitative rather than quantitative expressions. 

However, issues of scale and aggregation are important. 

Both the NRC report (2001) and the SAB review of the 

EPA’s Draft Report on the Environment (EPA SAB, 2005) 

emphasize the importance of using regional and local 

indicators. Over-aggregating information can obscure 

critical ecological threats or problems. In general, allowing 

sensitivity analysis on disaggregated data is desirable if the 

data are aggregated at a regional or higher level. So while 

some authors recommend simple summary indicators (e.g., 

Schiller et al., 2001; Failing and Gregory, 2003), others 

emphasize disaggregating indicators (EPA SAB, 2003).

45. For more information, see the analysis of survey 

techniques available on the SAB Web site at http://

yosemite.epa.gov/sab/sabproduct.nsf/WebBOARD/CVPESS_Web_Methods_Draft?OpenDocument.

46. This analysis evaluated the benefits and costs of amendments 

to the Clean Air Act passed by Congress in 1990. Its effort to 

evaluate the ecological benefits of these amendments raises 

many of the same issues that arise in evaluating the benefits 

of national rules. The prospective analyses compare the 

sequence of increasingly stringent rules called for under the 
120

1990 Clean Air Act Amendments with a situation where the 

rules were held constant at their 1990 levels (e.g., with the 

regulatory regime prior to the amendments). 

47. The one exception is the national survey on water quality 

conducted in the 1980s by Carson and Mitchell (1993), 

but this survey is not appropriate for use by the Agency in 

valuing ecosystem services, for reasons discussed later in 

section 6.1.2 and in endnote 49. 

48. Random utility models are a form of discrete choice model 

in which each individual’s choice of a recreation activity to 

take part in or recreation site to visit is assumed to depend 

on the characteristics of the available activities or sites as 

well as the individual’s socio-economic characteristics and 

variables reflecting preferences. The estimated parameters 

of the model can be used to calculate the values revealed 

by the choices made. For more information, see the section 

on travel cost models available on the SAB Web site at 

http://yosemite.epa.gov/Sab/Sabproduct.nsf/WebFiles/

Non-MarketRevealedPref/$File/Nonmarket-revealedpref-03-09-09.pdf.

49. A more recent national survey regarding willingness to pay 

for water quality improvements was conducted in 2004 

(see Viscusi et al., In press). This research was funded by 

EPA and used a nationally-representative web-based panel 

of over 4000 respondents from the Knowledge Network. 

Participants in the survey were asked questions designed 

to reveal their willingness to pay to increase the percentage 

of water in their region that was rated “good” according to 

the EPA’s National Water Quality Inventory ratings. EPA’s 

rating scale is based primarily, albeit not exclusively, on 

end uses relating to swimming and fishing. Carson and 

Mitchell (1993) used the water quality ladder to describe 

Examples of federal surveys (see endnote 35)

Continuously Funded Surveys Agency Sponsor Years

Survey of Income and Program Participation Census Bureau 1984-present

Consumer Expenditure Surveys Census Bureau 1968-present

Survey of Consumer Attitudes and Behavior National Science Foundation 1953-present

Health and Nutrition Examination Surveys National Center for Health Statistics 1959-present

National Health Interview Survey National Science Foundation 1970-present

American National Election Studies National Science Foundation 1948-present

Panel Study of Income Dynamics National Science Foundation 1968-present

General Social Survey National Science Foundation 1972-present

National Longitudinal Survey Bureau of Labor Statistics 1964-present

Behavioral Risk Factor Surveillance System Centers for Disease Control and Prevention 1984-present

Monitoring the Future National Institute of Drug Abuse 1975-present

Continuing Survey of Food Intake by Individuals Department of Agriculture 1985-present

National Aviation Operations Monitoring System National Aeronautics and Space Administration 2002-present

National Survey of Drinking and Driving National Highway Traffic Safety Administration 1991-present

National Survey of Family Growth National Center for Health Statistics 1973-present

National Survey of Fishing, Hunting, and WildlifeAssociated RecreationCensus Bureau 1991-present

National Survey of Child and Adolescent Well-Being Department of Health and Human Services 1997-present

Survey of Earned Doctorates National Science Foundation 1958-present

National Survey on Drug Use and Health Department of Health and Human Services 1971-present

Youth Risk Behavior Surveillance System Department of Health and Human Services 1990-present

National Crime Victimization Survey Bureau of Justice Statistics 1973-present

Schools and Staffing Survey National Center for Educational Statistics 1987-present

Educational Longitudinal Survey National Center for Educational Statistics 2002-present

Current Employment Statistics Survey Bureau of Labor Statistics 1939-present

Other Major Federally-Funded Surveys Agency Sponsor

National Survey of Distracted and Drowsy Driving National Highway Traffic Safety Administration

National Survey of Veterans Department of Veteran Affairs

National Survey of Children’s Health Health Resources and Services Administration’s Maternal and 

Child Health Bureau

National Survey of Recent College Graduates National Science Foundation

National Survey of Speeding and Other Unsafe Driving 

Actions

Department of Transportation
121

with a quantitative scale changes in water quality. The 

scale was defined as an index with associated activities that 

related primarily to recreational uses. Viscusi et al. provide 

a definition of ratings of water quality as good based on 

standards used by EPA and the states. No scale is used to 

quantitatively link the rating to a measure of water quality 

conditions. Their description includes recreation and other 

services supported by “good” conditions, but there is not 

an explicit link to specific ecosystem services or to specific 

water bodies. In addition, the water bodies are described 

using geographical designations – national versus regional 

water bodies. Thus, the study does not clearly link values 

to specific changes in ecosystem services. 

50. See the table below that lists major Chicago Wilderness 

reports and a its chronology of valuation efforts.

51. In one 1996 poll, only two out of ten Americans had 

heard of the term “biological diversity.” Yet when the 

concept was explained, 87% indicated that “maintaining 

biodiversity was important to them” (Belden and 

Russonello, 1996, as cited in the Chicago Wilderness 

Biodiversity Recovery Plan, p. 117).

Major Chicago Wilderness reports and chronology of valuation effort (see endnote 50)

Decision/document Date

Biodiversity Recovery Plan 1999 (Award from APA in 2001 for best 

plan)

Chicago Wilderness Green Infrastructure Vision Final report, March 2004

Green Infrastructure Mapping 2002

A Strategic Plan for the Chicago Wilderness Consortium 17 March 2005

Chicago Wilderness Regional Monitoring Workshop final report by Geoffrey Levin February 2005

Center for Neighborhood Technology (CNT) – green infrastructure valuation calculator Copyright 2004-2007
Key to photos

Front cover

Glacial ecosystems 

provide wilderness 

tourism and eco-tourism 

opportunities (p.31), a 

large percentage of the 

world’s available fresh 

water, and habitat for 

sea life.

Ecosystems supporting 

bees play a vital role in 

human life, such as food 

plant pollination (p. 8).

Horses rely on grasslands 

for forage, an ecosystem 

service (p. 8).

Chapter 1

There is an increasing 

recognition of the impact 

of land conversions that 

lead to loss of wetlands 

and biodiversity (p. 8).

Global warming has 

impact on arctic species 

and poses a growing 

threat for biodiversity 

(p. 8).

Some authors call 

for a common list of 

ecosystem services. 

Such a list might include 

wilderness as a land 

cover type (p. 34).

Recreational fishing is 

an ecosystem service 

(p. 69).

Lakes provide ecosystem 

services, such as 

recreation, as well as less 

well recognized services, 

such nutrient-cycling 

supporting aquatic 

species (p. 30).

Carbon sequestration 

has been studied as 

an ecosystem service. 

Agricultural systems 

contain carbon in soil, 

roots, and above-ground 

biomass (p. 31).

Chapter 3

Wetlands provide 

regulating services such 

as flood protection, water 

purification, air quality 

maintenance, and climate 

control (p. 82).

Scientists are defining 

ecological production 

functions for certain 

ecosystem services, such 

as pollination (p.31).

Agricultural ecosystems 

provide food, fiber, 

forage, and fuel, essential 

services for human life 

(p. 8).

Chapter 2

When ecological 

changes leads to a small 

change in commercial 

fishing harvests, the 

market price of fish can 

be used as a measure of 

willingness to pay for 

that marginal change 

(p. 46).

Social-psychological 

approaches have been 

used to study human 

perception of visual air 

quality (p. 44).

Native plants, such 

as wildflowers, are 

reservoirs of genes 

that may be useful for 

ecosystem survival. 

Conservation value 

methods study impacts 

on biodiversity (p. 50).

Chapter 4

Invertebrate fauna in 

wetlands provide food 

for waterfowl and help 

with water treatment, 

biological control, and 

erosion control, indirect 

services often not 

generally recognized or 

understood (p. 8).

Scientists, the public, and 

decision makers have 

engaged in deliberative 

processes to assess the 

value of protecting forest 

resources (p. 55).

Changes in leaf area 

are one of many factors 

related to complex 

ecological effects. Any 

study of current or past 

ecological conditions 

will have numerous 

interrelated uncertainties 

(p. 59).

Chapter 5

For national rule making, 

EPA can use research at 

local and regional scales 

(such as watersheds) to 

support national-scale 

analyses (p.20).

Economists have used 

hedonic, travel cost, 

and stated preference 

analyses to study 

recreational values of 

environmental amenities 

Another approach 

examines referenda 

voting to infer values 

for open space and other 

environmental amenities 

(p. 45-48).

Analyses for site 

restoration should 

identify directly 

experienced, measurable, 

and spatially and 

temporally explicit 

ecosystem services, such 

as viewing bald eagles 

and other species (p. 94).

Chapter 6

Supporting services 

maintain basic ecosystem 

processes and functions 

such as providing habitat 

for wolves (p. 12).

Provisioning services 

provide products such 

as food, fuel, fiber, 

biochemicals, genetic 

resources, and fresh 

water (p. 12).

Besides formal 

benefit-cost analysis, 

EPA should provide 

information about 

important types of value 

that may not be fully 

reflected in economic 

values, such as the value 

of wilderness (p. 23).

Chapter 7
Photos by Eric Vance and other photographers, U.S. EPA, courtesy of U.S. EPA.
SAB

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U.S. Environmental Protection Agency 

Mailcode 1400F 

1200 Pennsylvania Avenue, NW 

Washington, DC 20460 

http://www.epa.gov/sab 

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