prompt_front: You are given two reports by the government agency.



Question: Write a one-page summary of the report 1.

Report 1: Congressional rules establish a general division of responsibility under which questions of policy are kept separate from questions of funding  Broadly, the term authorization is used to describe legislation that establishes, continues, or modifies the organization or activities of a federal entity or program  By itself, such legislation does not provide funding for such purposes  Instead, the authority to obligate payments from the Treasury is left to separate appropriations measures  This distinction between appropriations and general legislation as two separate classes of measures, and their consideration in separate legislative vehicles, is a construct of congressional rules and practices  It has been developed and formalized by the House and Senate pursuant to the constitutional authority for each chamber to "determine the Rules of its Proceedings " This power permits each chamber of Congress to enforce, modify, waive, repeal, or ignore its rules as it sees fit  Because the two chambers exercise this rulemaking authority independently, they have developed differing (albeit generally similar) rules and practices  This report addresses solely developments in the House  According to Hinds' Precedents , the origin of a formal rule mandating the separation of general legislation from appropriations can be traced to 1835, when the House debated the increasing problem of delay in enacting appropriations due to the inclusion of "debatable matters of another character, new laws which created long debates in both Houses" and suggested that the Committee on Ways and Means should "strip the appropriation bills of every thing but were legitimate matters of appropriation " In the following Congress (25 th Congress, 1837-1839), language was added to House rules that stated: No appropriation shall be reported in such general appropriation bills, or be in order as an amendment thereto, for any expenditure not previously authorized by law  This rule was applied broadly on occasion to exclude legislative provisions authorizing new expenditures as well, such as a case in 1838 when it was used to exclude an amendment that included a provision for refurnishing the White House  Gradually, the rule "became construed through a long line of decisions to admit amendments increasing salaries but as excluding amendments providing for decreases " As a consequence of this, in 1876, the language was expanded (at the suggestion of Representative William Holman of Indiana) to further state: Nor shall any provision in any such bill or amendment thereto, changing existing law, be in order except such as, being germane to the subject matter of the bill, shall retrench expenditures  As described by one scholar, this provision effectively granted the Appropriations Committee authority to include virtually any legislative provision in an appropriations measure so long as it reduced the number and salary of federal officials, the compensation of any person paid out of the Treasury, or the amounts of money covered in an appropriation bill  According to one contemporary account, a broad initial construction of the rule by the House resulted in "putting a great mass of general legislation upon the appropriation bills " The rule was retained in this form until 1880 (46 th Congress), when it was modified to define retrenchments as the reduction of "the number and salary of officers of the United States, the reduction of compensation of any person paid out of the Treasury of the United States, or the reduction of the amounts of money covered by the bill " That form of the rule remained a part of House rules until the 49 th Congress eliminated it in 1885  It was reinserted in the rules for the 52 nd and 53 rd Congresses (1891-1895) but was again dropped for the 54 th through 61 st Congresses (1895-1911) before being readopted in the 62 nd Congress  Although the Holman rule has remained a part of House rules since that time, its language was amended at the start of the 98 th Congress (1983-1984)  At that time, it was restructured to narrow the exception to the general prohibition against legislation to allow only retrenchments reducing amounts of money covered by the bill  In addition, the House rules for the 98 th Congress changed when retrenchment amendments could be offered  Amendments that only alter the items or amounts in an appropriation bill are generally in order when the measure is read for amendment and must be offered as the relevant paragraph or section of the bill is read  The new version of the rule provided, however, that germane amendments to retrench expenditures (as well as limitation amendments) would be in order only after the reading of a general appropriation bill and if a preferential motion that the Committee of the Whole rise and report (essentially ending consideration of the bill) were rejected  Further stylistic changes were made when the House recodified its rules in the 106 th Congress (1999-2000) to make explicit that retrenchment amendments are in order if the motion to rise and report is not offered—as well as if the motion is rejected  It also clarified that the effect of a point of order against legislation in an appropriations bill (and, by extension, the application of the Holman rule exception) is surgical so that it lies against an offending provision in the text and not against consideration of the entire bill  The Holman rule currently states the following: A provision changing existing law may not be reported in a general appropriation bill, including a provision making the availability of funds contingent on the receipt or possession of information not required by existing law for the period of the appropriation, except germane provisions that retrench expenditures by the reduction of amounts of money covered by the bill [emphasis added]  The Holman rule, thus, does not circumscribe Congress's lawmaking authority but rather provides a limited exception to the general prohibition in House rules against legislation in appropriation measures  For the 115 th Congress, the House included a separate order as Section 3(a) of H Res  5 , adopting the rules of the House, that provides the following: During the first session of the One Hundred Fifteenth Congress, any reference in clause 2 of rule XXI to a provision or amendment that retrenches expenditures by a reduction of amounts of money covered by the bill shall be construed as applying to any provision or amendment (offered after the bill has been read for amendment) that retrenches expenditures by— (1) the reduction of amounts of money in the bill; (2) the reduction of the number and salary of the officers of the United States; or (3) the reduction of the compensation of any person paid out of the Treasury of the United States  As stated in a section-by section summary included in the Congressional Record by Representative Pete Sessions, the chairman of the House Rules Committee, the purpose of this provision is "to see if the reinstatement of the Holman rule will provide Members with additional tools to reduce spending during consideration of the regular general appropriation bill " The applicability of this separate order was extended under Section 5 of H Res  787 (115 th Congress) which provided that "Section 3(a) of House Resolution 5 is amended by striking 'the first session of '" This separate order was not adopted for the 116 th Congress, so the application of the rule reverts to being guided by prior precedents rather than this language  Since the period immediately after the initial adoption of the rule in the 19 th century, the House has interpreted it through precedents that have tended to incrementally narrow its application  For example, early precedents established that while it was not always necessary that a retrenchment specify the amount of a reduction of expenditures, it must appear as a necessary result of the legislation to be in order and that it is not sufficient that such reduction would probably (or would in the opinion of the chair) result therefrom  For example, legislation that would simply confer discretionary authority to terminate employment of federal employees is not in order under the Holman exception because any resulting savings would be speculative  The reduction also may not be contingent on an event  Furthermore, the rule is not applicable to funds other than those appropriated in the pending general appropriations bill  The Holman rule then is intended to apply only when an obvious reduction of funds in a general appropriations bill is achieved by the provision in question, such as the cessation of specific government activities, or through a specific reduction of total appropriations in the bill  In addition, the exception does not apply to limitations (on the grounds that such language is not legislative) or legislative language unaccompanied by a reduction of funds in the bill  Legislation that is too broad has also typically not been allowed under the Holman rule exception  The House has held, for example, that a provision that stated no part of an appropriation could be expended for a specific, designated purpose qualified as a retrenchment  However, a proposal that effectively repealed the law under which appropriations for that purpose were authorized was held not to come within the exception  In another case, the House held that even when a provision does reduce expenditures, it may not be accompanied by additional legislative provisions not directly contributing to the reduction  The separate order for the 115 th Congress effectively reinstated language that had been stricken from the rule in 1983  While the full scope of amendments might be in order as a consequence of this language, it is possible to analyze its potential impact based on past precedents and the limited experience of the 115 th Congress  The additional language opened the door to the consideration of retrenchments resulting from a reduction of the number and salary of the officers of the United States or the reduction of the compensation of any person paid out of the Treasury of the United States  There are precedents regarding provisions allowed under the older, pre-1983 form of the rule that may be illustrative for understanding what might be in order  For example, a proposal that pay for a class of employees be limited to a smaller number of employees than authorized by law was allowed, as were proposals that would reduce the number of officers  The Holman rule also allowed proposals that would consolidate or eliminate offices  On at least one occasion, the Holman rule was the basis for allowing a proposal to replace civilian employees with lower paid U S  Army enlisted personnel  In another case, the rule allowed for an amendment that capped the salaries of certain employees  In the 115 th Congress, one amendment was considered in order based on a plain reading of the text of the separate order to allow for "the reduction of the compensation of any person paid out of the Treasury of the United States " Although the amendment failed of passage, it would have provided that: The salary of Mark Gabriel, the Administrator of the Western Area Power Administration, shall be reduced to $1  As cited above, however, neither the rule nor the separate order allows for retrenchments that would be applicable to funds other than those appropriated in the pending general appropriations bill  In addition, the application of the broader exceptions in the separate order were still subject to the general requirement for germaneness  The Holman rule is not intended to open the door for legislative provisions that would expand the scope of the bill  As a consequence, even with the additional scope provided by the language of the separate order, it would likely not be in order to include broad legislative provisions in, or amendments to, a specific appropriation bill that would apply to the salary or number of federal employees funded through appropriations in other measures  Furthermore, House precedent establishes that simply providing for a reduction of the number and salaries of officers in a paragraph when it is complicated by other elements does not necessarily bring a proposition within the exception  The Holman rule was also cited as the basis for allowing the consideration of one additional amendment during the 115 th Congress  That amendment also failed to pass, but it would have abolished the Budget Analysis Division of the Congressional Budget Office, comprising 89 employees with annual salaries aggregating $15 million, transferring responsibility for any duties imposed by law and regulation to the Office of the Director of the Congressional Budget Office  When discussing the application of rules and precedents, it is important to note that the House Parliamentarian is the sole definitive authority on questions relating to the chamber's precedents and procedures and should be consulted if a formal opinion on any specific parliamentary question is desired 


Report 2:  The processes for developing and updating estimates are designed to inform management about program progress and the use of program resources, supporting cost-driven planning efforts and well-informed decision making  Our work has identified a number of best practices for use in developing guidance related to cost estimation and analysis that are the basis of effective program cost estimating and should result in reliable and valid cost estimates that management can use for making informed decisions  In 2012 we reported that the Bureau had not yet established guidance for developing cost estimates  We recommended that the Bureau establish guidance, policies, and procedures for developing cost estimates that would meet best practice criteria  The Bureau agreed with the theme of the report but did not specifically agree with the recommendation  Moreover, in June 2016, we also reported that the cost estimation team did not record how and why it changed assumptions that were provided to it and did not document the sources of all data it used  The documentation of these changes to assumptions did not happen because the Bureau lacked written guidance and procedures for the cost estimation team to follow  During this review we found the Bureau has since established reliable guidance, processes, and policies for developing cost estimates and managing the cost estimation process  The following documents, shown in table 2, establish roles and responsibilities for oversight and approval of cost estimation processes, provide a detailed description of the steps taken to produce a high-quality cost estimate, and clarify the process for updating the cost estimate and associated documents over the life of a project  The Decennial Census Program’s Cost Estimate and Analysis Process, which provides a detailed description of the steps taken to produce a high-quality estimate, is reliable as it met the criteria for 8 steps and substantially met the criteria for 4 steps of the 12 best steps outlined in our Cost Estimating and Assessment Guide, as shown below in figure 8  To avoid cost overruns and to support high performance, it will be important for the Bureau to abide by their newly developed policies and guidance and continue to use the life-cycle cost estimate as a management tool  The 2017 life-cycle cost estimate includes significantly higher costs than those included in the 2015 estimate  In 2015, the Bureau estimated that they could conduct the operation at a cost of $12 3 billion in constant 2020 dollars  The Bureau’s latest cost estimate, announced in October 2017, reflects the same design, but at an expected cost of $15 6 billion  Figure 9 below shows the change in cost by WBS category for 2015 and 2017  The largest increases occurred in the Response, Managerial Contingency, and Census/Survey Engineering categories  Increased costs of $1 3 billion in the response category (costs related to collecting, maintaining, and processing survey response data) were in part due to reduced assumptions for self-response rates, leading to increases in the amount of data collected in the field, which is more costly to the Bureau  Contingency allocations increased overall from $1 35 billion in 2015 to $2 6 billion in 2017, as the Bureau gained a greater understanding of risks facing the 2020 Census  Increases of $838 million in the Census/Survey Engineering category were due mainly to the cost of an IT contract for integrating decennial survey systems that was not included in the 2015 cost estimate  Bureau officials attribute a decrease of $551 million in estimated costs for Program Management to changes in the categorization of costs associated with risks: In the 2017 version of the estimate, estimated costs related to program risks were allocated to their corresponding WBS element  More generally, factors that contributed to cost fluctuations between the 2015 and 2017 cost estimates include: changes in assumptions for census operations, improved ability to anticipate and quantify risk, an overall increase in IT costs, and more defined contract requirements  Several assumptions for the implementation of the 2020 Census have changed since the 2015 cost estimate  Some assumptions contributing to cost changes, mainly in the Response (related to collecting and processing response data) and Frame (the mapping and collecting addresses to frame enumeration activities) categories, include the following: Self-response rates  Changes in assumptions for expected self- response rates contributed to increases in the response category, as the assumed rate decreased from 63 5 percent in 2015 to 60 5 percent in 2017, thereby increasing the anticipated percentage and associated cost of nonresponse follow-up  When the Bureau does not receive responses by mail, phone, or Internet, census enumerators visit each nonresponding household to obtain data  Thus, reduced self-response rates lead to increases in the amount of data collected in the field, which is more costly to the Bureau  Bureau officials attributed this decrease to a forecasted reduction in Internet response due to added authentication steps at log in and the elimination of the function allowing users to save their responses and return later to complete the survey  Productivity rates  The productivity of enumerators collecting data for NRFU is another variable in the cost estimate that was updated, contributing to cost increases in the response category  Expected productivity rates for NRFU decreased from the 2015 estimate of 4 attempts per hour to 2 9  According to Bureau documentation, this more conservative estimate is based on historical data, rather than research and test data  In-office address canvassing rates  The Bureau will not go door-to- door to conduct in-field address canvassing across the country to update address and map information for every housing unit, as it has in prior decennial censuses  Rather, some areas would only need a review of their address and map information using computer imagery and third-party data sources—what the Bureau calls “in-office” address canvassing procedures  However, in March 2017, citing budget uncertainty the Bureau decided to discontinue one of the phases of in-office review address canvassing for the 2020 Census  The cancellation of that phase of in-office review is expected to increase the number of housing units canvassed in-field by 5 percent (from 25 to 30 percent of all canvassed housing units)  In-field canvassing is more labor intensive compared to in office procedures  The 2017 version of the cost estimate reflects this increase in workload for in-field address canvassing, though overall changes in estimated costs for the Frame category, of which Address Canvassing is a part, were minimal  Staffing  Updated analysis resulted in changes to several staffing assumptions, which resulted in decreases across WBS categories  Changes included reduced pay rates for field data collection staff based on current labor market conditions and reductions in the length of staff engagement  In general, contingency allocations increased overall from $1 35 billion in 2015 to $2 6 billion in 2017  This increase in contingency can be attributed, in part, to the Bureau gaining a clearer understanding of risk and uncertainty in the 2020 Census as it approaches  The Bureau developed some of its contingency based on proven risk management techniques, including Monte Carlo analysis and allocated funding for known risk scenarios  The 2017 estimate includes close to $1 4 billion in estimated costs for these risks, almost three times the amount included in the 2015 estimate  The basis of estimate contains detail on the various risks and the process for calculating the associated contingency  The 2017 version also includes a contingency amount of $1 2 billion for general risks, or unknown-unknowns, such as natural disasters and cyber-attacks  Contingency amounts were reallocated within the WBS to more closely reflect the nature of the risk: Bureau officials attribute a decrease from the 2015 estimate of $551 million in estimated costs for program management to changes in the categorization of costs associated with risks  Officials stated that, in 2015, discrete program risks were previously consolidated as program management costs  In 2017, these discrete costs were reallocated to associate risks with the appropriate WBS element  For example, contingency amounts related to the likelihood of achieving a certain response rate previously included in the program management work breakdown category are now a part of the “response” work breakdown category  Increases in IT costs, totaling $1 59 billion, represented almost 50 percent of the total cost increase from 2015 to 2017  The total share of IT costs as a percentage of total census costs increased from 28 percent in 2015 to 32 percent in 2017, or from $3 41 billion to approximately $5 billion  Increases in IT costs are spread across seven cost categories  Figure 10 shows the IT and non-IT cost by WBS for the 2017 cost estimate  IT costs in infrastructure, response data, and census/survey WBSs account for the majority of the approximately $5 billion  The Bureau’s October 2015 cost estimate included IT costs for, among other things, system engineering, test and evaluation, and infrastructure, as well as for a portion of the Census Enterprise Data Collection and Processing (CEDCaP) program  The 2017 estimated IT cost increases were due, in large part, to the Bureau (1) updating the cost estimate for CEDCaP; (2) including an estimate for technical integration services that contributed to increases in the Census and Survey Engineering category; and (3) updating costs related to other major contracts (such as mobile device as a service, field IT services, and payroll systems)  Bureau documents described an overall improvement in the Bureau’s ability to define and specify contract requirements  This resulted in updated estimates for several contracts, including for the Census Questionnaire Assistance (CQA) contract  Assumptions regarding call volume to the CQA were increased by 5 percent to account for expected response by phone after the elimination of the option to save Internet responses and return to complete the form later  The Bureau also cited updated cost data and the results of reconciliation with independent cost estimates as factors contributing to the increased costs of other major contracts, including for the procurement of data collection devices  The Secretary of Commerce provided comments on a draft of this report on August 2, 2018  The comments are reprinted in appendix II  The Department of Commerce generally agreed with our findings regarding the improvements the Census Bureau has made in its cost estimates  However, Commerce did not agree with our assessment that the Bureau’s 2017 lifecycle cost estimate is “not reliable ” Commerce noted that it had conducted two independent cost analyses and was satisfied that the cost estimate was reliable  The Bureau also provided technical comments that we incorporated, as appropriate  We maintain that, to be considered reliable, a cost estimate must meet or substantially meet the criteria for each of the four characteristics outlined in our Cost Estimating and Assessment Guide  These characteristics are derived from measures consistently applied by cost estimating organizations throughout the federal government and industry and are considered best practices for the development of reliable cost estimates  Without a reliable cost estimate, the Bureau is limited in its ability to make informed decisions about program resources and to effectively measure progress against operational objectives  Thus, while the Bureau has made considerable progress in all four of the characteristics, it has only partially met the criteria for the characteristic of being well-documented  Until the Bureau meets or substantially meets the criteria for this characteristic, the cost estimate cannot be considered reliable  As agreed with your offices, unless you publicly announce the contents of this report earlier, we plan no further distribution until 30 days from the report date  At that time, we will send copies of the report to the appropriate congressional committees, the Secretary of Commerce, the Under Secretary of Economic Affairs, the Acting Director of the U S  Census Bureau, and other interested parties  In addition, this report is available at no charge on the GAO website at http://gao gov  If you or your staff have any questions about this report, please contact me at (202) 512-2757 or goldenkoffr@gao gov  Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this report  GAO staff who made key contributions to this report are listed in appendix III  The purpose of our review was to evaluate the reliability of the Census Bureau’s (Bureau) life-cycle cost estimate using our Cost Estimating and Assessment Guide  We reviewed (1) the extent to which the Bureau’s life-cycle cost estimate and associated guidance met our best practices for cost estimation using documentation and information obtained in discussions with the Bureau related to the 2020 life-cycle cost estimate and (2) compared the 2015 and 2017 life-cycle cost estimates to describe key drivers of cost growth  For both objectives we reviewed documentation from the Bureau on the 2020 life-cycle cost estimate and interviewed Bureau and Department of Commerce officials  For the first objective, we relied on our Cost Estimating and Assessment Guide as criteria  Our cost specialists assessed measures consistently applied by cost-estimating organizations throughout the federal government and industry and considered best-practices for developing reliable cost estimates  We analyzed the cost estimating practices used by the Bureau against these best practices and evaluated them in four categories: comprehensive, well-documented, accurate, and credible  Comprehensive  The cost estimate should include both government and contractor costs of the program over its full life-cycle, from inception of the program through design, development, deployment, and operation and maintenance to retirement of the program  It should also completely define the program, reflect the current schedule, and be technically reasonable  Comprehensive cost estimates should be structured in sufficient detail to ensure that cost elements are neither omitted nor double counted  Specifically, the cost estimate should be based on a product-oriented work breakdown structure (WBS) that allows a program to track cost and schedule by defined deliverables, such as hardware or software components  Finally, where information is limited and judgments are made, the cost estimate should document all cost-influencing assumptions  Well-documented  A good cost estimate—while taking the form of a single number—is supported by detailed documentation that describes how it was derived and how the expected funding will be spent in order to achieve a given objective  Therefore, the documentation should capture in writing such things as the source data used, the calculations performed and their results, and the estimating methodology used to derive each WBS element’s cost  Moreover, this information should be captured in such a way that the data used to derive the estimate can be traced back to, and verified against, their sources so that the estimate can be easily replicated and updated  The documentation should also discuss the technical baseline description and how the data were normalized  Finally, the documentation should include evidence that the cost estimate was reviewed and accepted by management  Accurate  The cost estimate should provide for results that are unbiased, and it should not be overly conservative or optimistic  An estimate is accurate when it is based on an assessment of most likely costs; adjusted properly for inflation; and contains few, if any, minor mistakes  In addition, a cost estimate should be updated regularly to reflect significant changes in the program—such as when schedules or other assumptions change—and actual costs, so that it is always reflecting current status  During the update process, variances between planned and actual costs should be documented, explained, and reviewed  Among other things, the estimate should be grounded in a historical record of cost estimating and actual experiences on other comparable programs  Credible  The cost estimate should discuss any limitations of the analysis because of uncertainty or biases surrounding data or assumptions  Major assumptions should be varied, and other outcomes recomputed to determine how sensitive they are to changes in the assumptions  Risk and uncertainty analysis should be performed to determine the level of risk associated with the estimate  Further, the estimate’s cost drivers should be cross-checked, and an independent cost estimate conducted by a group outside the acquiring organization should be developed to determine whether other estimating methods produce similar results  If any of the characteristics are not met, minimally met, or partially met, then the cost estimate does not fully reflect the characteristics of a high- quality estimate and cannot be considered reliable  We also analyzed the Bureau’s cost estimation and analysis guidance and evaluated them against a 12-step process outlined in our Cost Estimation and Assessment Guide  A high-quality cost estimating process integrates the following: 1  Define estimate’s purpose  2  Develop estimating plan  3  Define program characteristics  4  Determine estimating structure  5  Identify ground rules and assumptions  6  Obtain data  7  Develop point estimate and compare it to an independent cost estimate  8  Conduct sensitivity analysis  9  Conduct risk and uncertainty analysis  10  Document the estimate  11  Present estimate to management for approval  12  Update the estimate to reflect actual costs and changes  These 12 steps, when followed correctly, should result in reliable and valid cost estimates that management can use for making informed decisions  If any of the steps in the Bureau’s process do not meet, minimally meet, or partially meet the 12 steps, then the cost estimate guidance does not fully reflect best practices for developing a high-quality estimate and cannot be considered reliable  Lastly, to describe key drivers of cost growth, we compared cost information included in the 2015 and 2017 cost estimates  We analyzed both summary and detailed cost information to assess key changes in totals overall, by WBS category, and by information technology (IT) vs  Non-IT costs  We used this analysis in conjunction with information received from the Bureau during interviews and through document transfers to describe overall changes in the cost estimate from 2015 to 2017  We conducted this performance audit from December 2017 to August 2018 in accordance with generally accepted government auditing standards  Those standards require that we plan and perform the audit to obtain sufficient, appropriate evidence to provide a reasonable basis for our findings and conclusions based on our audit objectives  We believe that the evidence obtained provides a reasonable basis for our findings and conclusions based on our audit objectives  In addition to the contact named above, Lisa Pearson (Assistant Director), Karen Cassidy (Analyst in Charge), Brian Bothwell, Jackie Chapin, Ann Czapiewski, Jason Lee, Ty Mitchell, Kayla Robinson, and Tim Wexler made significant contributions to this report 

ground_truth: Although congressional rules establish a general division of responsibility under which questions of policy are kept separate from questions of funding, House rules provide for exceptions in certain circumstances. One such circumstance allows for the inclusion of legislative language in general appropriations bills or amendments thereto for "germane provisions that retrench expenditures by the reduction of amounts of money covered by the bill." This exception appears in clause 2(b) of House Rule XXI and is known as the Holman rule, after Representative William Holman of Indiana, who first proposed the exception in 1876. Since the period immediately after its initial adoption, the House has interpreted the Holman rule through precedents that have tended to incrementally narrow its application. Under current precedents, for a legislative provision or amendment to be in order, the legislative language in question must be both germane to other provisions in the measure and must produce a clear reduction of appropriations in that bill. In addition, the House adopted a separate order during the 115th Congress that provided for retrenchments of expenditures by a reduction of amounts of money covered by the bill to be construed as applying to: any provision or amendment that retrenches expenditures by— (1) the reduction of amounts of money in the bill; (2) the reduction of the number and salary of the officers of the United States; or (3) the reduction of the compensation of any person paid out of the Treasury of the United States. This separate order was not readopted for the 116th Congress. This report provides a history of this provision in House rules and an analysis of precedents that are illustrative of its possible application.

prompt_front: You are given two reports by the government agency.



Question: Write a one-page summary of the report 2.



Report 2: The U S  Fourth National Climate Assessment, released in 2018, concluded that "the impacts of global climate change are already being felt in the United States and are projected to intensify in the future—but the severity of future impacts will depend largely on actions taken to reduce greenhouse g as [GHG] emissions and to adapt to the changes that will occur " Although a variety of efforts seeking to reduce GHG emissions are currently underway on the international and sub-national level, federal policymakers and stakeholders have different viewpoints over what to do, if anything, about future climate change and related impacts  Their views regarding climate change cover a wide range of perspectives  For example, some contend that climate change poses a "direct, existential threat" to human society and that nations must start making significant reductions in GHG emissions in order to avoid "dire effects " To support this argument, proponents of climate change mitigation highlight the evidence and conclusions from recent reports that are generally considered authoritative, including: 1  The Intergovernmental Panel on Climate Change, Global W arming of 1 5°C , 2018; and 2  The U S  Global Change Research Program, Fourth National Climate Assessment , Volume II: Impacts, Risks, and Adaptation in the United States , 2018  On the other hand, some question whether there are sufficient risks of climate change to merit a federal program requiring GHG emission reductions  In addition, others argue that a unilateral approach to climate change by the United States could disproportionately impact domestic industries while achieving minimal results in global climate change mitigation  If Congress were to consider establishing a program to reduce GHG emissions, one option would be to apply a tax or fee on GHG emissions or the inputs that produce them  This type of approach is commonly called a carbon tax or a GHG emissions fee (see "Terminology Issues: A Carbon Tax or an Emissions Fee?")  This report does not compare and analyze the multiple policy tools available to Congress that could address climate change (see text box "Other Policy Options for Addressing GHG Emissions")  This report focuses on the policy considerations and potential impacts of using a carbon tax or GHG emissions fee to control GHG emissions  The key human-related GHG is CO 2 , which is generated primarily through the combustion of fossil fuels: coal, oil, and natural gas  In 2016, fossil fuel combustion accounted for 94% of U S  CO 2 emissions and 76% of U S  GHG emissions  A carbon tax could apply either directly to GHG emissions or to the materials—based on their carbon contents—that ultimately generate the emissions (i e , "emissions inputs")  A carbon price on emissions or their emissions inputs—mainly fossil fuels—would increase the relative price of the more carbon-intensive energy sources, particularly coal  This result could spur innovation in less carbon-intensive technologies (e g , renewable energy, nuclear power, carbon capture and sequestration [CCS]) and stimulate other behavior that may decrease emissions, such as efficiency improvements  The energy price increases could also have both economy-wide impacts and negative effects on specific industries and particular demographic groups  A carbon tax approach has received some attention and debate in recent years  In the 115 th Congress, Members introduced nine carbon tax or fee proposals  Outside of Congress, the Climate Leadership Council—a bipartisan group of former policymakers and industry leaders—published a conceptual carbon tax approach in 2017 that generated some interest  Some of the industry leaders on the council represent major energy companies, including Shell, BP, and ExxonMobil  On the other hand, many Members have expressed their opposition to a carbon tax  Starting in the 112 th Congress and going through the 115 th Congress, Members have introduced resolutions in both the House and Senate expressing the view that a carbon tax is not in the economic interests of the United States  In 2018, the House passed a resolution "expressing the sense of Congress that a carbon tax would be detrimental to the United States economy" ( H Con Res  119 )  An analogous resolution was not introduced in the Senate in the 115 th Congress  The first section of this report examines carbon tax design issues, including the point of taxation, the rate of taxation, and potential border carbon adjustments  The second section discusses issues related to the distribution of carbon tax revenues  The third section discusses additional considerations associated with a carbon tax program, including estimates of GHG emissions, federal revenue, and fossil fuel prices and changes in energy use  The fourth section provides concluding observations  If policymakers decide to establish a carbon tax system, Congress would face several key design decisions, including the point of taxation—where to impose the tax and what to tax—the rate of taxation, and whether and/or how to address imported carbon-intensive materials  Alternatively, Congress could direct one or more federal agencies to determine these design features through a rulemaking procedure  Although a few of the GHG emission reduction proposals in prior Congresses delegated such authority to an agency, such as the U S  Environmental Protection Agency (EPA), all of the proposals since the 111 th Congress have included some degree of design details in the statutory language  (A later section discusses carbon tax revenue application considerations ) The point of taxation would determine which entities would be required to (1) make tax payments based on emissions or emission inputs, such as fossil fuels, (2) monitor emissions or emission inputs, and (3) maintain records of relevant activities and transactions  This section provides some considerations for policymakers deciding which GHG emissions and/or emission sources to cover in a carbon tax system  Throughout the U S  economy, millions of discrete sources generate GHG emissions: power plants, industrial facilities, motor vehicles, households, commercial buildings, livestock, etc  Administrative costs and challenges would likely increase with a broader scope of an emissions tax  A carbon tax may apply to CO 2 emissions alone, which account for most U S  GHG emissions, or to multiple GHGs  Carbon tax proposals that apply only to CO 2 generally attach a price to a metric ton of CO 2 emissions (mtCO 2 )  Some sources emit non-CO 2 GHGs, such as methane, nitrous oxides, and sulfur hexafluoride  GHG emissions from these sources could be addressed by attaching a price to a metric ton of CO 2 emissions-equivalent (mtCO 2 e)  This term of measure is used because GHGs vary by global warming potential (GWP)  At these sources, the determined GWP values would be an important issue  Policymakers may consider limiting the tax to sectors or sources that emit above a certain percentage of total U S  GHG emissions, many of which currently report their emissions to the government  For more than 20 years, monitoring devices or systems have been installed in smokestacks of most large facilities, such as power plants, which are required to periodically report emissions data to EPA  In addition, since 2010, EPA has collected annual emissions data from approximately 8,000 facilities that directly release above certain amounts of GHG emissions  Using these established monitoring frameworks, policymakers could employ a "downstream" approach, applying a carbon tax at the point where the GHGs from these facilities are released to the atmosphere  Alternatively, the tax could be applied to reliable proxies for emissions, such as emission inputs  For example, the carbon content of fossil fuels—coal, natural gas, petroleum—can serve as a proxy for the emissions released when the fuels are combusted  Applying a tax on emission inputs allows for the consideration of various points of taxation  For instance, emission inputs could be taxed at "upstream" (e g , wells) or "midstream" stages in that process (e g , refineries), the latter allowing for potential tax administration advantages that may be provided by specific infrastructure chokepoints in the fossil fuel market  For example, with respect to petroleum, the number of upstream sources—wells that produce crude oil—is over 445,000, but the number of midstream sources—facilities that refine crude oil—is only 137  Table A-1 (in Appendix A) lists the top GHG emission sources in the United States  These sources combined to account for approximately 95% of U S  GHG emissions in 2016  Table A-1 identifies the number of entities for each source category (e g , number of coal mines, number of steel production facilities) and the percentage of total U S  GHG emissions the category contributes  In the case of fossil fuel combustion—which accounted for 76% of total U S  GHG emissions—the table provides several options for segmenting the universe of sources if policymakers choose to implement a carbon tax  It identifies the number of entities that might be subject to the carbon tax under a particular option (pending any exclusions)  For example, policymakers could address fossil fuel combustion emissions by applying a carbon tax to fossil fuels (based on their carbon content) at the following entities, which include both upstream and midstream infrastructure chokepoints: 137 petroleum refineries (based on 2017 data) and 166 petroleum importers (based on 2018 data); 671 coal mines and eight companies supplying imported coal (based on 2017 data); and 1,679 entities that report natural gas deliveries to the Energy Information Administration (EIA) on Form EIA-176 and 123 natural gas fractionators (based on 2016 data)  Some of the above points of taxation might take advantage of the administrative frameworks for existing federal excise taxes  For example, a per-barrel federal excise tax on crude oil at the refinery supports the Oil Spill Liability Trust Fund  An excise tax on the sale or use of coal supports the Black Lung Disability Trust Fund  A central policy choice when establishing a price on GHG emissions is the rate of the carbon tax  Several approaches, which are discussed below, could inform the decision  One approach would set the carbon tax rate at a level or pathway—based on modeling estimates—that would achieve a specific GHG emissions target  For example, a 2018 study estimated the carbon tax rate needed to meet the U S  GHG emission reduction targets established under the 2015 Paris Agreement: 26%-28% below 2005 net GHG emission levels by 2025  The study found that a constant tax rate of $43/ton starting in 2019 would meet the 2025 reduction target  Emissions reduction estimates from carbon tax programs are based on multiple assumptions  Accordingly, such estimates provide different tax rates needed to meet a particular emissions target depending on these assumptions  See " Impacts on GHG Emission Levels " for selected analyses of emission reductions for a given carbon price and rate of price increase  Under another approach, policymakers could base the carbon tax rate on the estimated marginal net benefits associated with reduced CO 2 emissions  The net benefits would be the avoided net damages (i e , costs) of climate change  The estimates of net benefits of avoided emissions often rely on analyses of the social cost of carbon (SC-CO 2 ) or the social cost of greenhouse gases (SC-GHG )  Therefore, policymakers could use SC-CO 2 measurements—as the basis for an estimate of the net benefits of a marginal change in emissions—to set the rate of a carbon tax or emissions fee  One potential challenge of relying on SC-CO 2 estimates to set a carbon fee are methodological concerns  For example, the existing estimates in peer-reviewed research cover a wide range  In addition, some argue that the underlying simulation models for estimating the SC-CO 2 values are insufficient  For any level of emissions, the projected increase in global average temperature may cover multiple degrees Fahrenheit, and other measures of climate change, such as precipitation patterns, may encompass directional uncertainties  No estimates of impacts are comprehensive at this time, and many of the risks are difficult to estimate and value  When valuing the SC-CO 2 , analysts encounter a range of views on methods and assumptions, and establishing study parameters may be challenging  For example, estimates of the monetary values of climate change impacts may be difficult or controversial to estimate, such as the monetary values associated with human deaths or sickness  A related framework question is whether to include global climate impacts or just domestic impacts  In addition, the element of time in climate change impacts particularly complicates the valuation  The fact that many impacts of climate change will occur in the distant future requires consideration of society's willingness to pay in the near term to reduce emissions that would cause future damages, mostly to future generations  To take time into account, economists discount future values to a calculated "present value " Economists do not agree on the appropriate discount rate(s) to use for a multi-generational, largely nonmarket issue such as human-induced climate change  The choice of discount rate can significantly increase or decrease values of the SC-CO 2   A low discount rate would give greater value today to future impacts than would a higher discount rate  High discount rates can reduce the value today of future climate change impacts to a small fraction of their undiscounted values  A high discount rate would recommend applying fewer of today's resources to addressing climate change impacts in the future  Since 2008, federal agencies have used SC-CO 2 estimates in dozens of final rulemakings as a method to estimate the net benefits of abating CO 2 emissions  An Interagency Working Group prepared SC-CO 2 estimates, which were updated over time and subjected to expert and public comment  On March 28, 2017, President Trump issued Executive Order 13783, "Promoting Energy Independence and Economic Growth," which effectively withdrew the federal SC-CO 2 estimates  Nonetheless, federal agencies have used new, interim values generated by EPA in 2017, modified from the withdrawn technical support documents, in regulatory and other decisions  Legislation could set a carbon price citing any of these SC-CO 2 values or others available from nonfederal researchers or prescribe methods for estimating new ones  Using SC-CO 2 estimates to set the tax rate would involve a cost-benefit framework  Although many posit that a cost-benefit framework remains the best option, some economists argue that a cost-benefit framework may be inappropriate for climate change policy for these reasons Many experts expect climate change—and policies to address it—to cause nonmarginal changes to economies and ecosystems  The changes are expected to increase disproportionately with incremental climate change with a potential for crossing critical "tipping points" after which systems change dramatically and rapidly  Climate change impacts are multi-generational, and uncertainty and disagreement exists about whether and how to assign a present value to social costs and benefits over generations  Some impacts from climate change may be irreversible on the timescale of human civilizations, such as melting of major ice sheets in Antarctica or Greenland  Policymakers might consider a carbon tax as a fiscal tool to help reduce the federal deficit, reduce other taxes, or pay for specific programs that may or may not be related to climate change policy  In addition, some have proposed a phased-in approach, setting a rate that is initially lower but increases at an announced or adjustable rate either for a fixed period or indefinitely  Advantages of this approach include providing an opportunity for consumers and investors to adjust their behavior before the higher tax rates go into effect, such as purchasing more energy efficient appliances or investing in low-emissions technologies  Phasing in a carbon tax, however, could delay climate-related benefits  If Congress finds agreement in principle on carbon pricing, the rate(s) could emerge from the process of reaching political agreement  Elements that might be considered include the options described above or consideration of the magnitude of overall economic impact; impacts on certain economic sectors, regions, or population groups; timing to motivate and allow an orderly transition to a lower-GHG economy; or other factors  Many stakeholders have voiced concerns over how a U S  carbon price system would interact with policies in other nations, particularly if the United States were to enact a carbon tax system that covers more sources or is more stringent than enacted elsewhere  A central concern is that a U S  carbon tax could raise U S  prices more than the prices of goods manufactured abroad, potentially creating a competitive disadvantage for some domestic businesses  Certain businesses may become less profitable, lose market share, and reduce jobs  The industries generally expected to experience disproportionate impacts under a U S  carbon tax are often described as "emission-intensive, trade-exposed" industries  An industry's CO 2 emission intensity is a function of both direct CO 2 emissions from its manufacturing process (e g , CO 2 from cement or steel production) and indirect CO 2 emissions from the inputs to the manufacturing process (e g , electricity, natural gas)  Such industries are likely to experience greater cost increases than less carbon intensive industries, all else being equal  In general, trade-exposed industries are those that face greater international competition compared to other domestic industries  A carbon tax could present a particular challenge for these industries, because they might be less able to pass along the tax in the form of higher prices, because they may lose global market share—and jobs—to competitors in countries lacking comparable carbon policies  Policymakers might consider approaches to mitigate these potential economic impacts in several ways  One approach that has received interest in recent years is a border adjustment mechanism, which is often described as a border carbon adjustment (BCA) in the carbon tax context  A BCA would apply a tariff to emission-intensive, imported goods such as steel, aluminum, cement, and certain chemicals  Each of the carbon price proposals in the 115 th Congress would have established a BCA to address emission-intensive imports  Another rationale for adding a BCA to a carbon tax system is the possibility that it would encourage other nations to adopt comparable carbon price policies  Many of the recently proposed BCA mechanisms allow for exemptions for nations with comparable programs  To date, no nations have implemented a BCA as part of their climate change policies  Establishing an economically efficient BCA would likely present substantial challenges  For example, policymakers must decide which goods and/or industries would be covered by a BCA and how the adjustment program would assess the comparability of varied climate-related policies in other nations  In addition, accurately determining and verifying the volume of GHG emissions embodied in a particular imported product would be data intensive and challenging  To alleviate some of the measurement complexity, policymakers could limit the program to selected industries and apply default values and assumptions to particular manufacturing processes  However, this simplified approach could result in less accurate import price adjustments, which could potentially affect the accuracy of GHG emission reductions achieved by the carbon tax program  Another option would be to allow companies to provide measured, independently verified emissions data as an alternative to default values  In addition, the border adjustment approach would likely raise concerns of violating international trade rules  Further, some researchers have highlighted the potential for unintended consequences from a BCA  For example, some studies have found that a border adjustment may lead to lower net exports than the carbon price alone, due to the adjustment's terms-of-trade effect on U S  currency  These issues are beyond the scope of this report, but some of the concerns may be lessened to some degree if a larger number of nations establish comparable emission reduction policies, as many have agreed to do under the Paris Agreement  Another possible rationale for a BCA is to address the concern of "emissions leakage" (or "carbon leakage")  Emissions leakage "occurs when economic activity is shifted as a result of the emission control regulation [e g , a carbon tax program] and, as a result, emission abatement achieved in one location that is subject to emission control regulation is [diminished] by increased emissions in unregulated locations " The concern of emissions leakage has been central in the debate over whether the United States (or any nation) should unilaterally address GHG emissions  A BCA may diminish the potential for emissions leakage by reducing the incentive to shift economic activity to a nation without a comparable carbon tax  However, some recent studies raise questions regarding the degree to which emissions leakage would be a concern under a unilateral U S  carbon tax  Although a tax may be levied on fossil fuels or GHG emission sources at various points in the economy, the carbon tax impacts may be experienced elsewhere  Policymakers have multiple options to address these expected impacts  Policymakers would face challenging decisions regarding the distribution of the new carbon tax revenues  As discussed below, some economic analyses indicate that certain distributions of tax revenue—depending on the level of the tax—would have a greater economic impact than the direct effects from the tax or fee on GHG emissions  Carbon tax revenues could be treated as general fund revenue without a dedication to a specific purpose in the enacting legislation (i e , subject to the annual appropriations process), or policymakers could state that the new revenues would support deficit (or debt) reduction  Alternatively, the enacting legislation could return the tax revenue to the economy in some manner, sometimes called "revenue recycling " All of the carbon tax legislative proposals in recent Congresses have proposed some manner of revenue recycling, specifically directing the carbon tax revenue to support specific policy objectives  Carbon tax revenues may be used to support a variety of policy goals  When deciding how to allocate the new revenue stream, policymakers would likely encounter trade-offs among objectives, including: reducing the economy-wide costs resulting from a carbon tax program; alleviating the costs borne by subgroups in the U S  population, particularly low-income households and/or communities most dependent on carbon-intensive economic activity; and supporting specific policy objectives, such as domestic employment, climate change adaptation, energy efficiency, technological advance, energy diversity, or federal deficit reduction, among others  In general, economic carbon tax studies have found that the relative ranking of revenue recycling options to mitigate the economy-wide impacts is generally the opposite of the relative ranking for alleviating distributional impacts  The contrasting relative rankings highlight a central tradeoff policymakers would face when deciding how to allocate carbon tax revenues  The following sections discuss these trade-offs and some of the revenue application options that have received attention in recent years  A large body of economic literature has examined the economic impacts of hypothetical carbon tax programs, particularly the impacts of using the carbon tax revenues for different purposes  Many of the economic studies cited below were prepared prior to the enactment of the Tax Cuts and Jobs Act (TCJA, P L  115-97 )  Signed by President Trump in December 2017, the act changed various elements of the U S  federal tax system  In particular, the act lowered the corporate income tax rate from 35% to 21%  As discussed below, adjusting the corporate income tax rate is one of the central policy options generally considered in carbon tax economic literature both before and after enactment of P L  115-97   Based on a selected review of the economic literature that includes the tax code changes in P L  115-97 , the central conclusions from carbon tax literature regarding revenue recycling appear to be largely unchanged  A primary concern with a carbon tax is the potential economy-wide costs that may result  Generally, a tax or fee on GHG emissions or the fuels that generate them would increase certain energy prices, namely fossil fuels, in the near- to medium-term as well as the prices of goods and services produced using these materials, like electricity  This outcome is inherent to the carbon tax, as its purpose is to increase the relative price of the more carbon-intensive energy sources compared to less carbon-intensive alternatives, encourage innovation in less carbon-intensive technologies, and promote other activity (e g , energy efficiency) that may decrease emissions  These expected outcomes will have some economy-wide impacts  Ultimately, the economy-wide effects would depend on a number of factors, including, but not limited to, the magnitude and scope of the carbon tax and, most importantly, use of the ensuing revenues  Economy-wide costs (referred to as macroeconomic costs) are often measured in terms of changes in projected gross domestic product (GDP) or another societal-scale metric, such as economic welfare  The magnitude of macroeconomic impacts from a carbon tax has been a subject of debate among policymakers and stakeholders  In addition, results of economy-wide impacts will not include comparisons of impacts to different subpopulations or geographic regions, which may be of interest to policymakers  Multiple economic studies and models have examined and compared various options for addressing the economy-wide impacts that may result from a carbon tax  One option for reducing the economic cost of a carbon tax is using the revenue to reduce existing taxes, such as those on labor, income, and investment  Economists generally describe such taxes as distortionary, because the taxes discourage economically beneficial activity, such as employment and investment  Another option for policymakers is to use the tax revenues to address the national debt  Fewer studies have examined deficit reduction scenarios, because "modeling the effects of budget deficits is much more difficult than modeling the effects of tax cuts " Some studies have concluded that using tax revenues for this purpose would help alleviate economy-wide costs from a carbon tax because of the reduced need to impose distortionary taxes in the future  These studies indicate that the economy-wide benefit would be delayed and its realization assumes policymakers would, sometime in the future, address the deficit by raising taxes  Many recent legislative proposals would distribute the carbon tax revenue back to households in lump-sum payments  Policymakers have generally included this carbon tax revenue application to address distribution impacts (discussed below)  These payments could take multiple forms  Economic analyses typically assume an equal payment to individuals or households regardless of their income or location or the effects of the carbon price on them individually  Alternatively, payments could be targeted or scaled to different segments of the population  Among the options mentioned above, economic studies indicate that using carbon tax revenues to offset reductions in existing, distortionary taxes would be the most economically efficient use of the revenues and yield the greatest benefit to the economy overall  This concept is sometimes referred to as a "tax swap " Using carbon tax or fee revenues to offset other distortionary taxes (e g , labor or capital) may yield a "double-dividend," which includes: reduced GHG emissions; and reduced market distortions by reducing other distortionary taxes, such as investment or income  The economic models that examine the economic impacts of a carbon tax differ in their frameworks and underlying assumptions and often include multiple scenarios involving different uses of carbon tax revenue  In general, the economic models find that certain revenue recycling options may reduce the economy-wide carbon tax impacts but may not eliminate them entirely  Some studies cite particular economic modeling scenarios in which a carbon tax with certain revenue recycling applications would produce a net increase in GDP or economic welfare compared to a baseline scenario  These results indicate that, in certain modeling conditions, the economic improvements gained by reducing existing distortionary taxes would be greater than the costs imposed by the new carbon tax (without including the intended climate benefits of the policy)  For example, results from a 2018 study demonstrated a net increase in GDP, compared to baseline conditions, when carbon tax revenues were used to finance proportionate reductions in labor tax rates (payroll tax)  In general, the economic carbon tax studies usually agree on the relative ranking of revenue recycling options in terms of their ability to mitigate the economy-wide impacts of a carbon tax program  The studies indicate that the approaches that use carbon tax revenue to proportionately lower existing tax rates are able to mitigate more of the carbon tax economy-wide costs than using the revenue to provide a lump-sum distribution to individuals or households  Researchers prepared multiple carbon tax analyses prior to the enactment of the TCJA in 2017 that estimated the magnitude GDP impacts  As with other estimates relating to carbon tax impacts, the results depend on the scope of the carbon tax, underlying assumptions in the analytical model, and the terms of measurement: Some estimates measure GDP growth rates; others measure actual GDP  Figure 1 illustrates the modeled GDP results from a 2018 carbon tax analysis that includes the changes made by the TCJA  This study assessed the GDP impacts under a $50/mtCO 2 e carbon tax (starting in 2020 and increasing by 2% annually) that would apply to CO 2 emissions from fossil fuel combustion and methane emissions from fossil fuel production activities  The figure compares projected GDP impacts under a baseline scenario (i e , no carbon tax) with three carbon tax revenue applications: a payroll tax rate reduction tax swap, a lump-sum distribution to households, and a scenario that would use tax revenue to reduce the national debt for 10 years and then use revenues for a lump-sum distribution to households  The figure projects GDP impacts in 2020, 2024, 2029, and 2039  As the figure indicates, the payroll tax rate scenario would result in a 0 1% loss of GDP in the first year (2020), but would yield GDP gains in subsequent years compared to baseline  The lump-sum distribution approach would yield GDP losses each year, ranging from 0 3% to 0 4% below the projected baseline  The deficit reduction approach would yield a range of GDP losses in the first 10 years—ranging from 0 4% to 0 04%—but would yield a GDP gain in 2039 (if not before), compared to baseline  Opponents of a carbon tax approach often highlight the GDP losses that would result from a carbon tax  Policymakers and stakeholders may have different perspectives regarding whether the magnitude of the GDP impacts are significant  In addition, GDP impact estimates may be presented in several ways  For example, one could compare the differences in GDP value for a particular year between carbon tax scenarios and a baseline scenario  This approach is employed in the above figure  Alternatively, one could present the GDP losses with a cumulative measure  For instance, if one were to add up the annual GDP losses (for example, over a 10-year period) from the lump-sum scenario compared to the baseline scenario, the resulting sum would be much larger  These types of calculations would require assumptions about annual GDP growth rates  Some may point out that the GDP impact estimates do not account for the environmental and public health benefits for reducing GHG emissions and that the GDP projections should be compared with the climate benefits achieved from the program as well as the estimated costs of taking no action  As discussed above, estimates of climate-related benefits and costs often contain considerable uncertainty and have generated debate in recent years  Many economic analyses have found that a carbon tax (before revenue recycling) would produce a regressive outcome among households, with lower-income households facing a larger impact from the tax than higher-income households  However, "the degree to which a carbon tax is found to disproportionately burden low-income households varies across studies, based on the metrics against which analysts measure costs " Entities that pay the carbon tax may pass its costs back to fuel producers or forward to fuel consumers  If entities pass the costs forward, consumers would face higher prices for fuels and electricity and carbon-intensive products  When the carbon tax is passed forward to consumers, lower-income households in particular would likely face a disproportionate impact (i e , regressive outcome), because a larger percentage of their income is used to pay for energy needs, such as electricity, gasoline, or home heating oil  Many economic analyses of carbon price scenarios assume that the vast majority (if not all) of the carbon tax impact is passed forward to consumers, leading to a regressive outcome  On the other hand, if entities pass the costs backward to producers, the tax impacts would fall on labor through reduced wages or owners of capital through reduced returns on investment  Economic models that assume this outcome produce more progressive results (absent revenue recycling), with lower-income households experiencing smaller impacts than higher-income households  The economic analyses appear to agree that the distributional effects among households (i e , regressive vs  progressive) of a carbon tax program would be largely dependent on how the carbon tax revenues were used  A number of economic studies have used models to estimate the impacts of a carbon tax across households under several revenue distribution scenarios  The results vary because the studies use different modeling frameworks, carbon tax rates and scopes, underlying assumptions, and ways to measure impacts  For example, a 2018 study assessed the impacts to household income for different household quintiles under a carbon tax of $50/mtCO 2 e, starting in 2020  This study examined four revenue distribution scenarios: 1  reduce federal deficit, 2  reduce corporate income tax rate, 3  reduce payroll tax rate, and 4  provide a per-capita rebate to households  This report highlights this study, because it includes carbon tax revenue applications that have generated interest in recent years  In addition, this analysis was prepared after the 2017 tax rate changes in P L  115-97   Figure 2 illustrates the modeled results, which the study measured as percentage reductions to household income  Thus, negative percentages illustrated in the figure are gains to household income  The per-capita rebate approach provides the most progressive result, yielding a net benefit for the bottom three household quintiles but a net loss for the top quintile  The fourth quintile impact is zero  By comparison, the other approaches produce varying degrees of regressive outcomes while providing a net gain for wealthier groups in two particular instances  Of the four options, the payroll tax rate reduction approach estimates the smallest variance between the income quintiles, ranging from a 0 5% loss for the lowest quintile to a 0 2% gain for the fourth quintile  The fifth quintile impact is zero  The relative ranking among options for progressivity is generally the opposite of the relative ranking for mitigating economy-wide impacts  Other economic analyses have found similar relative rankings of revenue recycling options  The contrasting rankings highlight a central tradeoff policymakers would face when deciding how to allocate carbon tax revenues  Policymakers could allot some portion of the revenues to partially support both objectives  In a 2018 carbon tax study, economic modelers assessed a scenario in which a portion of the revenue was used to offset the welfare impacts for the lowest-income household quintile and the remaining revenue supported reductions in capital tax rates  The study's models estimated that a carbon tax's impacts on the lowest-income household quintile could be counteracted with approximately 10% of the revenue  This would allow for 90% of the revenue to be used to reduce capital tax rates and thus address the economy-wide impacts from the carbon tax  As discussed above, a carbon tax is projected to disproportionately impact certain industries, particularly those that are described as "emission-intensive, trade-exposed industries " To address these concerns, many of the recent carbon tax legislative proposals have included design mechanisms that would attach a carbon price to certain imported materials and products (see " Border Carbon Adjustments ")  Another approach to addressing the competitiveness concerns of domestic industries would involve distributing a portion of the carbon tax revenues to emission-intensive, trade-exposed industries as rebates based on their output  Output rebate proposals generally determine rebate amounts by measuring emissions intensity at the relevant sector level or by a benchmark that would encourage facilities to reduce their emissions intensity  These rebates could be phased out over time or continue until other nations adopt comparable carbon price policies  Under a carbon tax system in Canada, which is scheduled to take effect in 2019, industries will be subject to an "output-based pricing system " Some contend that the data and administrative resources necessary to implement such a program would be substantial  A carbon tax system is also expected to disproportionately impact fossil fuel industries and the communities that rely on their employment  In particular, coal-mining communities are expected to experience substantial impacts based on the coal production declines predicted in carbon tax analyses  For example, one model estimates that under a $50/mtCO 2 e carbon tax, annual U S  coal production would decline by almost 80% in 2030 compared to a reference case  Policymakers may consider supporting worker transition or community transition assistance to help mitigate the economic impacts  Several of the recent carbon tax proposals would have devoted carbon tax revenues for this objective  Policymakers may also consider using the carbon tax revenues to provide funding to support a range of objectives, which may include policy goals that are not directly related to climate change  Some options are identified below, and many have been included in recent legislative proposals or in state GHG mitigation programs that raise revenues: Technology development and deployment: Efforts to reduce the costs of emission mitigation technologies—particularly carbon capture, utilization, and sequestration—are often considered in carbon tax programs, and Congress has funded such programs in other legislation  Energy efficiency programs: Although a carbon tax would likely stimulate energy efficiency to some degree, Congress may consider using the revenues to provide additional incentives and/or technical assistance, particularly to encourage households and small businesses to increase efficiency, which would also reduce the effects of the tax on their energy bills  States in the Regional Greenhouse Gas Initiative (RGGI) have used revenues from the program to support efficiency improvements, among other objectives  Biological sequestration: Trees, plants, and soils sequester carbon, removing it from the earth's atmosphere  Revenues could be used to promote carbon sequestration efforts, particularly forestry or agricultural activities, which would supplement the GHG reductions of the carbon tax  Adaptation to climate change: Regardless of emission reduction efforts taken today, climatic changes are expected due to the ongoing accumulation of GHGs in the atmosphere  Therefore, some advocate using revenues to reduce potential damage—domestically and internationally—of a changing climate  Deficit reduction: The possible contribution of a carbon tax to deficit reduction would depend on the magnitude and scope of the carbon tax, various market factors, and assumptions about the size of the deficit  Some carbon tax proposals in recent congressional sessions would have allotted a portion of revenues for deficit reduction  Infrastructure funding: Some recent proposals have provided funding for infrastructure projects  This objective could be combined with funding for adaptation activities  Multiple economic studies have estimated the emission reductions that particular carbon tax designs could achieve  Economic models provide estimates based on the best information available at the time  Comparing results from different studies is problematic, because the studies' scenarios differ in multiple ways, including the tax rate, start date, scope of the program, assumptions about economic growth and technological advances, and assumptions about other federal and state policies and their effects  A 2018 study avoided some of these comparison difficulties by inviting modeling teams to analyze a coordinated set of scenarios  The 2018 Stanford Energy Modeling Forum study ("EMF 32") assembled 11 modeling teams to analyze the economic impacts of four carbon tax scenarios starting in 2020: a $25/metric ton and $50/metric ton carbon tax, increasing annually by 1% and 5%  Within each of these carbon price frameworks, the models ran separate revenue distribution scenarios: a reduction in labor tax rates, a reduction in capital tax rates, and household rebates  Figure 3 illustrates the study's estimates of CO 2 emissions from fossil fuel combustion  The red lines in the figure display the average values for the 11 models  The shaded areas illustrate the range of results, highlighting the uncertainties in emission reduction estimates  Based on these results, the study authors concluded that each of the tax rate scenarios would likely achieve the U S  CO 2 emission reduction targets under the Paris Agreement  As Figure 3 indicates, a carbon tax or emissions fee could be set with the expectation that it would achieve an emissions reduction target, but the resulting level of emissions would be uncertain  The uncertainty of resulting emissions may lead some stakeholders to disfavor a carbon tax or fee option to control GHG emissions  Although uncertain emissions are inherent with a carbon tax approach, Congress could employ certain design elements to enhance the emission control certainty  For example, the existing GHG emission reporting data could be used to track the impact and performance of a carbon price  If policymakers determine that emission reduction is not occurring at a desired pace, the price could be amended  Legislation could establish the conditions and process by which price changes could occur  Some may argue that adjusting the carbon price to reflect actual emissions performance would undermine the benefits of price certainty  Others may point out that unplanned adjustments to the carbon price could be politically unpalatable  For example, it may be difficult for policymakers to increase the tax rate, especially during periods of high energy prices  Some have suggested that Congress authorize an independent board or agency with the mandate to modify the tax rate administratively in order to meet pre-determined emission reduction objectives  Although this approach would likely improve emission certainty, long-term price certainty may be sacrificed to some degree, depending on the authority of the delegated entity to adjust the tax rate  Some would argue that potential year-to-year emission variations under a carbon tax would not undermine efforts to control climate change so long as long-term emission goals are achieved  Indeed, they would assert that annual emission fluctuations are preferable to price volatility that could result from an emissions cap program  They support their preference for price control by suggesting that CO 2 generates damages through its overall accumulation as concentrations in the atmosphere, not its annual flow  A potential concern of a carbon tax is whether it would be effective in reducing GHG emissions in all of its covered sectors, particularly emissions in the transportation sector  As of 2016, the transportation sector contributes the largest percentage (36%) of CO 2 emissions from fossil fuel combustion, with electric power second at 35%  Carbon tax analyses generally agree that the majority of the emission reductions resulting from a carbon tax program would occur in the electricity sector  By comparison, economic models generally conclude that a carbon tax would have much less of an impact on emissions in the transportation sector  Several factors explain this projected outcome  The transportation sector offers fewer opportunities to switch to less carbon-intensive fuels in the short term than does the electric power sector, which can displace coal with natural gas relatively quickly  In addition, short-term emission changes in the transportation sector are largely influenced by changes in driving demand, which has historically been relatively insensitive to gasoline price increases  Based on these projected outcomes, some may contend that to achieve deeper, long-term reductions in total GHG emissions, policymakers would need to complement a carbon tax with other programs, such as vehicle technology standards (e g , Corporate Average Fuel Economy, CAFE) or fuel performance standards, among other options  The quantity of revenues generated under a carbon tax system depend on the program's design features, namely the tax base and rate, as well as such independent factors as prices in global energy markets  They would also depend on how covered emission sources respond to the carbon price, for example by adopting alternative technologies or changing behavior  Several carbon tax studies have prepared revenue estimates, which are presented in Table 1   From a public finance perspective, a carbon tax may not be a reliable source of long-term funding, because a primary goal of the carbon tax is to reduce its tax base—GHG emissions  The estimates in Table 1 project carbon tax revenue values in 2020  Multiple studies have projected carbon tax revenue trajectories beyond 2020  In the 2018 EMF 32 study, all but one of eight models projected carbon tax revenue increases from 2020 through 2040  The carbon tax scenarios with larger annual rate increases resulted in steeper trajectories of increasing revenues through 2040  The models' estimates of annual carbon tax revenue in 2040 ranged from approximately $250 billion to $475 billion (under the tax rate scenario of $50/metric ton, increasing 5% annually)  Fossil fuels have a wide range of CO 2 emission intensity (i e , emissions per unit of energy)  As illustrated in Figure 4 , the CO 2 emission intensity of coal is approximately 30% more than oil and approximately 80% more than natural gas  These emissions intensity differences would lead to different tax rates per unit of energy across different fuels in a carbon tax regime  Carbon taxes could affect fuel prices in complex ways  The change in consumer fuel prices would likely not be the same as the price paid by the party directly subject to the tax  Actual price impacts for consumers would depend on multiple factors, including whether: a carbon tax is applied at the beginning of the production process ("upstream") to fossil fuels; and the price impacts are passed through to end users and not absorbed by upstream energy producers or midstream entities, such as retailers  In addition, market participants such as electric power plant operators can avoid paying the increased costs by substituting fuels or technologies  Energy consumers may modify their behavior in the marketplace—energy conservation, consuming less or different products and services—to mitigate impacts from the increased prices  Table 2 includes estimates of price increases on coal, crude oil, natural gas, home heating oil, and motor gasoline based on a carbon tax rate of $25/mtCO 2 that applies CO 2 emissions from fossil fuel combustion  As indicated in the table, a carbon tax would have the greatest impact on the price of coal due to coal's relatively high CO 2 emissions intensity  By comparison, a carbon tax is expected to have less of an impact on the price of gasoline, increasing its price by 8%  Economic models have projected how carbon prices would impact energy use, particularly the consumption of different fossil fuels and less carbon-intensive alternatives, such as renewables or nuclear power  For example, the 2018 EMF 32 study, which included results from 11 modeling groups, assessed how several carbon tax scenarios would impact energy consumption  Highlights of these models' results (compared to reference case scenarios) include the following: Coal consumption could decline by 40% to nearly 100% by 2030 under a $50/mtCO 2 carbon tax, though one model projected an increase in coal due to the model incorporating CCS technology  Natural gas consumption estimates vary across the models, with some showing minimal change in 2030 and others showing declines ranging between 40% and 60%  Oil consumption estimates indicate that the largest decline (approximately 4% by 2030) would occur under the $50/mtCO 2 carbon tax scenario  Wind energy consumption could increase by 48% to 300% by 2030 under a $50/mtCO 2 carbon tax scenario  A carbon tax is one policy option to address U S  GHG emission levels, which contribute to climate change and related impacts  Economic modeling indicates that a carbon tax would achieve emission reductions, the level of which would depend on which GHG emissions and sources are covered and the rate of the carbon tax  A carbon tax would generate a new revenue stream  The magnitude of the revenues would depend on the scope and rate of the tax and multiple market factors, which introduce uncertainty in the revenue projections  A 2018 CBO study estimated that a $25/metric ton tax on CO 2 emissions from energy-related activities and other selected GHG emission sources would yield approximately $100 billion in the first year of the program  To put this estimate in context, the CBO projected that total federal revenue would be $3 5 trillion in FY2019  Policymakers would face challenging decisions regarding the distribution of the new carbon tax revenues  Depending on the level of the tax, some economic analyses indicate that the distribution of tax revenue could yield greater economic impacts than the direct impacts of the tax  Some models indicate that the economic impacts are greatest in the early years of the carbon tax  Policymakers could apply the tax revenues to support a range of policy objectives  When deciding how to allocate the revenues, policymakers would encounter trade-offs among objectives  The central trade-offs involve minimizing economy-wide costs, lessening the costs borne by specific groups—particularly low-income households—and supporting a range of specific policy objectives  A primary concern with a carbon tax is the potential economy-wide costs that may result  The potential costs would depend on a number of factors, including the magnitude, design, and use of revenues of the carbon tax  In general, economic literature finds that some of the modeled revenue applications would reduce the economy-wide costs imposed by a carbon tax but may not eliminate them entirely  Policymakers and stakeholders may have different perspectives regarding whether these estimated economy-wide costs (typically measured in terms of GDP loss) represent a significant concern  Some argue that the estimated economy-wide costs should be compared with the policy option of not establishing a carbon tax  This comparison is uncertain as carbon tax analyses do not generally consider the benefits that would be gained by reducing GHG emissions and avoiding climate change and its adverse impacts  Some studies cite particular economic modeling scenarios in which a carbon tax and revenue recycling could produce a net increase in GDP or economic welfare, compared to a baseline scenario  These scenarios involve using carbon tax revenues to offset reductions in existing, distortionary taxes, such as corporate income or payroll taxes  Although the models indicate that these revenue applications would yield the greatest benefit to the economy overall, the models also find that lower-income households would likely face a disproportionate impact under such revenue applications  As lower-income households spend a greater proportion of their income on energy needs, these households are expected to experience disproportionate impacts from a carbon tax if revenues were not recycled back to them in some fashion, such as a lump-sum distribution  Carbon tax revenues that are used to offset the burden imposed on various sectors or specific population groups would not be available to support other objectives  An additional concern with a carbon tax involves potential disproportionate impacts to "emission-intensive, trade-exposed industries " Policymakers could select among several options to address these concerns, either by establishing a border carbon adjustment program or allocating some of the carbon tax revenues to selected industry sectors based on an output-based metric  If other nations were to adopt comparable carbon price policies, this concern may be alleviated to some degree  Relatedly, a carbon tax is projected to disproportionately impact fossil fuel industries, particularly coal, and the communities that rely on their employment  To alleviate these impacts, policymakers could allocate some of the carbon tax revenue to provide transition assistance to employees or affected communities  Table A-1 identifies sources of GHG emissions that account for 0 5% or more of total U S  GHG emissions  The sources are listed in descending order by their percentage contribution  CO 2 emissions from fossil fuel combustion, which accounts for almost 76% of total U S  GHG emissions, are broken down by fossil fuel type: petroleum, coal, and natural gas  The table identifies potential points in the economy at which a carbon tax could be applied  The table lists the approximate number of entities that would be involved with different tax applications  The number of entities listed is current as of the most recent data available and varies accordingly by category  See table notes for details  The right-hand column of the table provides additional comments for some of the emission sources  In some cases the comments discuss potential opportunities for additional GHG emissions coverage at a particular source  In other cases, the comments address potential limitations of covering all of the emissions from a particular source 
Report 2:  The processes for developing and updating estimates are designed to inform management about program progress and the use of program resources, supporting cost-driven planning efforts and well-informed decision making  Our work has identified a number of best practices for use in developing guidance related to cost estimation and analysis that are the basis of effective program cost estimating and should result in reliable and valid cost estimates that management can use for making informed decisions  In 2012 we reported that the Bureau had not yet established guidance for developing cost estimates  We recommended that the Bureau establish guidance, policies, and procedures for developing cost estimates that would meet best practice criteria  The Bureau agreed with the theme of the report but did not specifically agree with the recommendation  Moreover, in June 2016, we also reported that the cost estimation team did not record how and why it changed assumptions that were provided to it and did not document the sources of all data it used  The documentation of these changes to assumptions did not happen because the Bureau lacked written guidance and procedures for the cost estimation team to follow  During this review we found the Bureau has since established reliable guidance, processes, and policies for developing cost estimates and managing the cost estimation process  The following documents, shown in table 2, establish roles and responsibilities for oversight and approval of cost estimation processes, provide a detailed description of the steps taken to produce a high-quality cost estimate, and clarify the process for updating the cost estimate and associated documents over the life of a project  The Decennial Census Program’s Cost Estimate and Analysis Process, which provides a detailed description of the steps taken to produce a high-quality estimate, is reliable as it met the criteria for 8 steps and substantially met the criteria for 4 steps of the 12 best steps outlined in our Cost Estimating and Assessment Guide, as shown below in figure 8  To avoid cost overruns and to support high performance, it will be important for the Bureau to abide by their newly developed policies and guidance and continue to use the life-cycle cost estimate as a management tool  The 2017 life-cycle cost estimate includes significantly higher costs than those included in the 2015 estimate  In 2015, the Bureau estimated that they could conduct the operation at a cost of $12 3 billion in constant 2020 dollars  The Bureau’s latest cost estimate, announced in October 2017, reflects the same design, but at an expected cost of $15 6 billion  Figure 9 below shows the change in cost by WBS category for 2015 and 2017  The largest increases occurred in the Response, Managerial Contingency, and Census/Survey Engineering categories  Increased costs of $1 3 billion in the response category (costs related to collecting, maintaining, and processing survey response data) were in part due to reduced assumptions for self-response rates, leading to increases in the amount of data collected in the field, which is more costly to the Bureau  Contingency allocations increased overall from $1 35 billion in 2015 to $2 6 billion in 2017, as the Bureau gained a greater understanding of risks facing the 2020 Census  Increases of $838 million in the Census/Survey Engineering category were due mainly to the cost of an IT contract for integrating decennial survey systems that was not included in the 2015 cost estimate  Bureau officials attribute a decrease of $551 million in estimated costs for Program Management to changes in the categorization of costs associated with risks: In the 2017 version of the estimate, estimated costs related to program risks were allocated to their corresponding WBS element  More generally, factors that contributed to cost fluctuations between the 2015 and 2017 cost estimates include: changes in assumptions for census operations, improved ability to anticipate and quantify risk, an overall increase in IT costs, and more defined contract requirements  Several assumptions for the implementation of the 2020 Census have changed since the 2015 cost estimate  Some assumptions contributing to cost changes, mainly in the Response (related to collecting and processing response data) and Frame (the mapping and collecting addresses to frame enumeration activities) categories, include the following: Self-response rates  Changes in assumptions for expected self- response rates contributed to increases in the response category, as the assumed rate decreased from 63 5 percent in 2015 to 60 5 percent in 2017, thereby increasing the anticipated percentage and associated cost of nonresponse follow-up  When the Bureau does not receive responses by mail, phone, or Internet, census enumerators visit each nonresponding household to obtain data  Thus, reduced self-response rates lead to increases in the amount of data collected in the field, which is more costly to the Bureau  Bureau officials attributed this decrease to a forecasted reduction in Internet response due to added authentication steps at log in and the elimination of the function allowing users to save their responses and return later to complete the survey  Productivity rates  The productivity of enumerators collecting data for NRFU is another variable in the cost estimate that was updated, contributing to cost increases in the response category  Expected productivity rates for NRFU decreased from the 2015 estimate of 4 attempts per hour to 2 9  According to Bureau documentation, this more conservative estimate is based on historical data, rather than research and test data  In-office address canvassing rates  The Bureau will not go door-to- door to conduct in-field address canvassing across the country to update address and map information for every housing unit, as it has in prior decennial censuses  Rather, some areas would only need a review of their address and map information using computer imagery and third-party data sources—what the Bureau calls “in-office” address canvassing procedures  However, in March 2017, citing budget uncertainty the Bureau decided to discontinue one of the phases of in-office review address canvassing for the 2020 Census  The cancellation of that phase of in-office review is expected to increase the number of housing units canvassed in-field by 5 percent (from 25 to 30 percent of all canvassed housing units)  In-field canvassing is more labor intensive compared to in office procedures  The 2017 version of the cost estimate reflects this increase in workload for in-field address canvassing, though overall changes in estimated costs for the Frame category, of which Address Canvassing is a part, were minimal  Staffing  Updated analysis resulted in changes to several staffing assumptions, which resulted in decreases across WBS categories  Changes included reduced pay rates for field data collection staff based on current labor market conditions and reductions in the length of staff engagement  In general, contingency allocations increased overall from $1 35 billion in 2015 to $2 6 billion in 2017  This increase in contingency can be attributed, in part, to the Bureau gaining a clearer understanding of risk and uncertainty in the 2020 Census as it approaches  The Bureau developed some of its contingency based on proven risk management techniques, including Monte Carlo analysis and allocated funding for known risk scenarios  The 2017 estimate includes close to $1 4 billion in estimated costs for these risks, almost three times the amount included in the 2015 estimate  The basis of estimate contains detail on the various risks and the process for calculating the associated contingency  The 2017 version also includes a contingency amount of $1 2 billion for general risks, or unknown-unknowns, such as natural disasters and cyber-attacks  Contingency amounts were reallocated within the WBS to more closely reflect the nature of the risk: Bureau officials attribute a decrease from the 2015 estimate of $551 million in estimated costs for program management to changes in the categorization of costs associated with risks  Officials stated that, in 2015, discrete program risks were previously consolidated as program management costs  In 2017, these discrete costs were reallocated to associate risks with the appropriate WBS element  For example, contingency amounts related to the likelihood of achieving a certain response rate previously included in the program management work breakdown category are now a part of the “response” work breakdown category  Increases in IT costs, totaling $1 59 billion, represented almost 50 percent of the total cost increase from 2015 to 2017  The total share of IT costs as a percentage of total census costs increased from 28 percent in 2015 to 32 percent in 2017, or from $3 41 billion to approximately $5 billion  Increases in IT costs are spread across seven cost categories  Figure 10 shows the IT and non-IT cost by WBS for the 2017 cost estimate  IT costs in infrastructure, response data, and census/survey WBSs account for the majority of the approximately $5 billion  The Bureau’s October 2015 cost estimate included IT costs for, among other things, system engineering, test and evaluation, and infrastructure, as well as for a portion of the Census Enterprise Data Collection and Processing (CEDCaP) program  The 2017 estimated IT cost increases were due, in large part, to the Bureau (1) updating the cost estimate for CEDCaP; (2) including an estimate for technical integration services that contributed to increases in the Census and Survey Engineering category; and (3) updating costs related to other major contracts (such as mobile device as a service, field IT services, and payroll systems)  Bureau documents described an overall improvement in the Bureau’s ability to define and specify contract requirements  This resulted in updated estimates for several contracts, including for the Census Questionnaire Assistance (CQA) contract  Assumptions regarding call volume to the CQA were increased by 5 percent to account for expected response by phone after the elimination of the option to save Internet responses and return to complete the form later  The Bureau also cited updated cost data and the results of reconciliation with independent cost estimates as factors contributing to the increased costs of other major contracts, including for the procurement of data collection devices  The Secretary of Commerce provided comments on a draft of this report on August 2, 2018  The comments are reprinted in appendix II  The Department of Commerce generally agreed with our findings regarding the improvements the Census Bureau has made in its cost estimates  However, Commerce did not agree with our assessment that the Bureau’s 2017 lifecycle cost estimate is “not reliable ” Commerce noted that it had conducted two independent cost analyses and was satisfied that the cost estimate was reliable  The Bureau also provided technical comments that we incorporated, as appropriate  We maintain that, to be considered reliable, a cost estimate must meet or substantially meet the criteria for each of the four characteristics outlined in our Cost Estimating and Assessment Guide  These characteristics are derived from measures consistently applied by cost estimating organizations throughout the federal government and industry and are considered best practices for the development of reliable cost estimates  Without a reliable cost estimate, the Bureau is limited in its ability to make informed decisions about program resources and to effectively measure progress against operational objectives  Thus, while the Bureau has made considerable progress in all four of the characteristics, it has only partially met the criteria for the characteristic of being well-documented  Until the Bureau meets or substantially meets the criteria for this characteristic, the cost estimate cannot be considered reliable  As agreed with your offices, unless you publicly announce the contents of this report earlier, we plan no further distribution until 30 days from the report date  At that time, we will send copies of the report to the appropriate congressional committees, the Secretary of Commerce, the Under Secretary of Economic Affairs, the Acting Director of the U S  Census Bureau, and other interested parties  In addition, this report is available at no charge on the GAO website at http://gao gov  If you or your staff have any questions about this report, please contact me at (202) 512-2757 or goldenkoffr@gao gov  Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this report  GAO staff who made key contributions to this report are listed in appendix III  The purpose of our review was to evaluate the reliability of the Census Bureau’s (Bureau) life-cycle cost estimate using our Cost Estimating and Assessment Guide  We reviewed (1) the extent to which the Bureau’s life-cycle cost estimate and associated guidance met our best practices for cost estimation using documentation and information obtained in discussions with the Bureau related to the 2020 life-cycle cost estimate and (2) compared the 2015 and 2017 life-cycle cost estimates to describe key drivers of cost growth  For both objectives we reviewed documentation from the Bureau on the 2020 life-cycle cost estimate and interviewed Bureau and Department of Commerce officials  For the first objective, we relied on our Cost Estimating and Assessment Guide as criteria  Our cost specialists assessed measures consistently applied by cost-estimating organizations throughout the federal government and industry and considered best-practices for developing reliable cost estimates  We analyzed the cost estimating practices used by the Bureau against these best practices and evaluated them in four categories: comprehensive, well-documented, accurate, and credible  Comprehensive  The cost estimate should include both government and contractor costs of the program over its full life-cycle, from inception of the program through design, development, deployment, and operation and maintenance to retirement of the program  It should also completely define the program, reflect the current schedule, and be technically reasonable  Comprehensive cost estimates should be structured in sufficient detail to ensure that cost elements are neither omitted nor double counted  Specifically, the cost estimate should be based on a product-oriented work breakdown structure (WBS) that allows a program to track cost and schedule by defined deliverables, such as hardware or software components  Finally, where information is limited and judgments are made, the cost estimate should document all cost-influencing assumptions  Well-documented  A good cost estimate—while taking the form of a single number—is supported by detailed documentation that describes how it was derived and how the expected funding will be spent in order to achieve a given objective  Therefore, the documentation should capture in writing such things as the source data used, the calculations performed and their results, and the estimating methodology used to derive each WBS element’s cost  Moreover, this information should be captured in such a way that the data used to derive the estimate can be traced back to, and verified against, their sources so that the estimate can be easily replicated and updated  The documentation should also discuss the technical baseline description and how the data were normalized  Finally, the documentation should include evidence that the cost estimate was reviewed and accepted by management  Accurate  The cost estimate should provide for results that are unbiased, and it should not be overly conservative or optimistic  An estimate is accurate when it is based on an assessment of most likely costs; adjusted properly for inflation; and contains few, if any, minor mistakes  In addition, a cost estimate should be updated regularly to reflect significant changes in the program—such as when schedules or other assumptions change—and actual costs, so that it is always reflecting current status  During the update process, variances between planned and actual costs should be documented, explained, and reviewed  Among other things, the estimate should be grounded in a historical record of cost estimating and actual experiences on other comparable programs  Credible  The cost estimate should discuss any limitations of the analysis because of uncertainty or biases surrounding data or assumptions  Major assumptions should be varied, and other outcomes recomputed to determine how sensitive they are to changes in the assumptions  Risk and uncertainty analysis should be performed to determine the level of risk associated with the estimate  Further, the estimate’s cost drivers should be cross-checked, and an independent cost estimate conducted by a group outside the acquiring organization should be developed to determine whether other estimating methods produce similar results  If any of the characteristics are not met, minimally met, or partially met, then the cost estimate does not fully reflect the characteristics of a high- quality estimate and cannot be considered reliable  We also analyzed the Bureau’s cost estimation and analysis guidance and evaluated them against a 12-step process outlined in our Cost Estimation and Assessment Guide  A high-quality cost estimating process integrates the following: 1  Define estimate’s purpose  2  Develop estimating plan  3  Define program characteristics  4  Determine estimating structure  5  Identify ground rules and assumptions  6  Obtain data  7  Develop point estimate and compare it to an independent cost estimate  8  Conduct sensitivity analysis  9  Conduct risk and uncertainty analysis  10  Document the estimate  11  Present estimate to management for approval  12  Update the estimate to reflect actual costs and changes  These 12 steps, when followed correctly, should result in reliable and valid cost estimates that management can use for making informed decisions  If any of the steps in the Bureau’s process do not meet, minimally meet, or partially meet the 12 steps, then the cost estimate guidance does not fully reflect best practices for developing a high-quality estimate and cannot be considered reliable  Lastly, to describe key drivers of cost growth, we compared cost information included in the 2015 and 2017 cost estimates  We analyzed both summary and detailed cost information to assess key changes in totals overall, by WBS category, and by information technology (IT) vs  Non-IT costs  We used this analysis in conjunction with information received from the Bureau during interviews and through document transfers to describe overall changes in the cost estimate from 2015 to 2017  We conducted this performance audit from December 2017 to August 2018 in accordance with generally accepted government auditing standards  Those standards require that we plan and perform the audit to obtain sufficient, appropriate evidence to provide a reasonable basis for our findings and conclusions based on our audit objectives  We believe that the evidence obtained provides a reasonable basis for our findings and conclusions based on our audit objectives  In addition to the contact named above, Lisa Pearson (Assistant Director), Karen Cassidy (Analyst in Charge), Brian Bothwell, Jackie Chapin, Ann Czapiewski, Jason Lee, Ty Mitchell, Kayla Robinson, and Tim Wexler made significant contributions to this report 

ground_truth: The U.S. Fourth National Climate Assessment, released in 2018, concluded that "the impacts of global climate change are already being felt in the United States and are projected to intensify in the future—but the severity of future impacts will depend largely on actions taken to reduce greenhouse gas [GHG] emissions and to adapt to the changes that will occur." Members of Congress and stakeholders articulate a wide range of perspectives over what to do, if anything, about GHG emissions, future climate change, and related impacts. If Congress were to consider establishing a program to reduce GHG emissions, one option would be to attach a price to GHG emissions with a carbon tax or GHG emissions fee. In the 115th Congress, Members introduced nine bills to establish a carbon tax or emissions fee program. However, many Members have expressed their opposition to such an approach. In particular, in the 115th Congress, the House passed a resolution "expressing the sense of Congress that a carbon tax would be detrimental to the United States economy." Multiple economic studies have estimated the emission reductions that particular carbon tax would achieve. For example, a 2018 study analyzed various impacts of four carbon tax rate scenarios: a $25/metric ton of CO2 and $50/metric ton of CO2 carbon tax, increasing annually by 1% and 5%. The study concluded that each of the scenarios would likely achieve the U.S. GHG emission reduction target pledged under the international Paris Agreement (at least in terms of CO2 emissions). A carbon tax system would generate a new revenue stream, the magnitude of which would depend on the scope and rate of the tax, among other factors. In 2018, the Congressional Budget Office (CBO) estimated that a $25/metric ton carbon tax would yield approximately $100 billion in its first year. CBO projected that federal revenue would total $3.5 trillion in FY2019. Policymakers would face challenging decisions regarding the distribution of the new carbon tax revenues. Congress could apply revenues to support a range of policy objectives but would encounter trade-offs among the objectives. The central trade-offs involve minimizing economy-wide costs, lessening the costs borne by specific groups—particularly low-income households and displaced workers in certain industries (e.g., coal mining)—and supporting other policy objectives. A primary argument against a carbon tax regards it potential economy-wide impacts, often measured as impacts to the U.S. gross domestic product (GDP). Some may argue that projected impacts should be compared with the climate benefits achieved from the program as well as the estimated costs of taking no action. The potential impacts would depend on a number of factors, including the program's magnitude and design and, most importantly, the use of carbon tax revenues. In general, economic literature finds that some of the revenue applications would reduce the economy-wide costs from a carbon tax but may not eliminate them entirely. In addition, some studies cite particular economic modeling scenarios in which certain carbon tax revenue applications produce a net increase in GDP compared to a baseline scenario. These scenarios involve using carbon tax revenues to offset reductions in other tax rates (e.g., corporate income or payroll taxes). Although economic models generally indicate that these particular revenue applications would yield the greatest benefit to the economy overall, the models also find that lower-income households would likely face a disproportionate impact under such an approach. As lower-income households spend a greater proportion of their income on energy needs (electricity, gasoline), these households are expected to experience disproportionate impacts from a carbon tax if revenues were not recycled back to them in some fashion (e.g., lump-sum distribution). A price on GHG emissions could create a competitive disadvantage for some industries, particularly "emission-intensive, trade-exposed industries." Policymakers have several options to address this concern, including establishing a "border carbon adjustment" program, which would levy a fee on imports from countries without comparable GHG reduction programs. Alternatively, policymakers could allocate (indefinitely or for a period of time) some of the carbon tax revenues to selected industry sectors or businesses. Relatedly, a carbon tax system is projected to disproportionately impact fossil fuel industries, particularly coal, and the communities that rely on their employment. To alleviate these impacts, policymakers may consider using some of the revenue to provide transition assistance to employees or affected communities.