Categorization of Government Information (CGI) Working Group

U.S. Federal Interagency Committee on Government Information

**[Requirements for Enabling the Identification, Categorization and
Consistent Retrieval of Government Information]{.smallcaps}**

August 5, 2004

Comments on this document may be sent to the editor (e-mail:
gschlag@gpo.gov)

1\. Objective [1](#objective)

2\. Background [2](#__RefHeading___Toc81021284)

3\. Assumptions [3](#assumptions)

4\. Constraints [5](#constraints)

5\. Major Stakeholders [6](#major-stakeholders)

6\. Process for Identifying Requirements
[9](#process-for-identifying-requirements)

7\. Major Requirements [9](#major-requirements)

Appendix 1: Scope of Definition [13](#appendix-1-scope-of-definition)

Appendix 2: Information on Searchable Identifiers
[15](#appendix-2-information-on-searchable-identifiers)

Appendix 3: Notes and References [17](#appendix-3-notes-and-references)

# 1. Objective

The U.S. Federal Government seeks to improve the methods by which
Government information, including information on the Internet, is
organized, preserved, and made accessible to the public, as required
under the E-Government Act of 2002, Section 207 "Accessibility,
Usability, and Preservation of Government Information." This document
provides a basis for recommendations to be submitted to the Office of
Management and Budget by U.S. Interagency Committee on Government
Information (ICGI).

This document defines the requirements for enabling the identification,
categorization and consistent retrieval of government information. It
specifically addresses what government information is categorizable,
what searchable identifiers are and how they can be applied to
government information. The requirement also addresses why Agencies and
Departments should apply categorization to improve search retrieval and
information value. In addition, the document identifies constraints
surrounding the implementation and identifiers and categorization
identifiers, identifies major stakeholders, and proposes major
requirements for their successful implementation.

# 2. Background

**Definitions**

A. The term \"categorizable Government information\" means any
information product, regardless of form or format, which an agency
discloses, publishes, disseminates, or makes available to the public, as
well as information produced for administrative or operational purposes
that is of public interest or educational value. This includes
information created or exchanged within or between agencies, and
information that is or may be expected to be subject to FOIA requests.
Not included are Federal government information holdings explicitly
provided in law as so constrained in access that even a reference to the
holding is kept from public view for a specified period of time.

This definition is focused on information products of interest to the
public, *produced by or for* the Government. However, it must be
recognized that cases will occur in which the publishing agency may
limit access to the descriptive metadata about certain products to
certain audiences for a specified period of time, due to security,
privacy, or other records management reasons.

The goal of agreeing upon, and ultimately implementing, a definition of
what information is to be categorized, is to enable citizens to obtain a
predictable body of search results, of similar granularity across
varying communities of practice.

B. Searchable identifiers as described in E-Government Act of 2002,
Section 207, have the following characteristics: they uniquely identify
an information object, support persistent access to that object, and
support access to information about the object, i.e., metadata.

C. Categorization is the process by which individual information
products can be associated with other products using vocabularies
designed to help citizens locate and access information. There can be
multiple attributes assigned to a product (e.g. multiple
categorizations). Categorization is used to provide context to a
specific product and to define relationships across a group of
information products.

# 3. Assumptions

## 3.1 Assumptions on What is to be Categorized 

Searchers of government information need to find tangible resources
(i.e. printed documents, maps, CDs, or DVDs) as well as intangible
(online electronic) resources produced by or for the Government. A
workable and understandable definition of resources to which the public
may reasonable expect to have ready access will enhance the active
support of information-producing agencies.

The recommended definition will take into account the range of
constraints that may apply to a particular information product. Use
constraints such as copyright restrictions may apply in certain cases
specifically allowed under law, such as patents. Access constraints may
apply to certain security classified information, proprietary
information, personal information, litigation-related information, and
other particular cases. For example, there is certain information for
which access is restricted to authorized public citizens such as (1)
Information restricted to private citizens eligible to receive that
data, (2) information limited to government contractors, (3) information
limited to state and local governments.

Citizens need consistent, reliable, and accurate access to government
information. The E-Government Act of 2002 mandates that information be
discoverable and interoperable across organizational boundaries.

Government information creation and maintenance is, and will remain, a
highly distributed activity. Therefore, categorization and identifier
assignment must also be distributed.

## 3.2 Assumptions for Searchable Identifiers

Searchable Identifiers are persistent and support information object
metadata to facilitate object management, authentication, digital rights
management, discovery, and other services. Searchable identifiers can
persistently identify both intangible and tangible information objects.
The current practice of using URLs to persistently reference digital
objects is not effective. A recent study by University of Nebraska
researchers found that the half-life of biochemistry and molecular
biology information links is 55 months (Markwell & Brooks, 2003).
Although there are no specific studies that address the prevalence of
broken links ("linkrot") for Government information objects, experience
indicates that it is significant.

The value of implementing and maintaining searchable identifiers will
exceed overall costs on a macro level. However, on the micro level,
costs for any particular organization may be relatively high and
represent a historically underfunded mandate and/or require an
additional level of expert personnel. Therefore, selection of the most
efficient, cost effective, least resource intensive approach will
enhance acceptance of the "burden" by the information generating
organizations.

The discovery of and persistent access to digital information will
encourage the increased use of and reliance on information. In addition,
by virtue of its reliable availability, persistently identified
information will encourage individuals and organizations to use it,
reuse it, and aggregate it in new and innovative ways. Technological
advances will render existing network protocols obsolete. Therefore,
searchable identifier schemes must be transferable to future, as yet
unknown, technologies.

Government organizations are in constant flux, e.g., changing missions,
reorganizations, downsizing, reduced resources, contractor changes,
ephemeral projects, and the termination of programs and organizations.
Some government information is sensitive. Consequently, any searchable
identification scheme will have to support both publicly available, and
sensitive, not publicly available, information.

Persistent identification is currently a service external to COTS
application software. In other words, vendors, e.g., Microsoft, have not
adopted a persistent identification scheme. Regardless of the searchable
identification scheme(s) adopted, organizations must make a commitment
to maintaining persistent access to information objects through
searchable identifiers and to maintaining the accuracy of the associated
metadata.

Reuse and integration of existing, successful identification approaches
into a searchable identifier scheme will increase acceptance and reduce
implementation costs.

## 3.3 Assumptions for Categorization

The primary assumption about the categorization of government
information is that with exponential increases in the amount of
information available, categorization and description becomes all the
more valuable. Being able to filter, sort, and prioritize information
within a large corpus improves the citizens' ability to evaluate the
information provided and make good choices about what to retain and use.

Another key assumption is that the technologies to use this descriptive
information (e.g. metadata) are evolving and will definitely change
substantially over the next five to ten years. The evolving concept of
the "semantic Web" assumes that this information will be captured as
information is created. Whatever the technological landscape, a set of
standards is possible that will allow for the capture, management and
sharing of this information across the government and between government
and the citizens.

This document also assumes the increased use of extensible tools
including schema and markup languages for the creation and management of
information resources. Extensibility allows for categorization to be
expanded to local, enterprise, and global standards and makes the
process of managing information one that builds on previous work rather
than constantly reinventing the wheel.

There are emerging requirements for categorization across a wide
spectrum of uses including records management and searchable
identifiers. Since these requirements will most likely identify a
minimal set of metadata for each object, we assume the requirement for
categorization would either correlate or mirror these other metadata
requirements.

Faceted Classification (categorization) recognizes that information is
multi-dimensional and that citizens do not always "know" an object name
but may be looking for information through other contextual aspects such
as who, what, how where, when, and why. This allows for multiple ways of
getting to the information based on function, purpose, audience level
and type.

# 4. Constraints

## 4.1 Constraints on What Information is to be Categorized 

The definition of resources to which CGI is applicable should not be so
all encompassing as to be unmanageable. It is possible to construe
Government information so broadly that information products about the
Government, such as television news coverage of Government activities,
objects owned by the Government, or owned by other parties and loaned to
the Government, such as museum artifacts, could be included. However, an
overly broad definition of CGI-eligible resources risks creating a
requirement so burdensome to the Government that the goal of improved
public access could be jeopardized.

The Federal government generally does not constrain access to or use of
its holdings and the data and information are in the public domain. Yet,
there are a range of constraints that may apply to any particular
holding. Use constraints such as copyright restrictions may apply in
certain cases specifically allowed under law, such as patents. Access
constraints may apply to certain security classified information,
proprietary information, personal information, litigation-related
information, and other particular cases. For example, there is certain
information for which access is restricted to authorized public citizens
such as (1) Information restricted to private citizens eligible to
receive that data, (2) information limited to government contractors,
(3) information limited to state and local governments.

## 4.2 Constraints for Searchable Identifiers

Available resources may be inadequate to support persistent
identification without negatively impacting other organizational
priorities. In other words, persistent identification may represent a
historically underfunded mandate. Since persistent identification is not
currently integrated into COTS products or existing networks, additional
expertise will be required to deploy and maintain persistent
identification and to develop required supporting policies and
procedures.

Although organizations will be acutely aware of the costs of
implementing a searchable identifier scheme and its possible impact on
their mission performance, the benefits, at least initially and because
they are diffuse, won't be as easy to quantify. Clearly, the widespread
implementation of searchable identifiers will have a profound "big
picture" impact on public access to government information. However, the
costs will not equal the benefits for each and every government
organization. The implementation and support of searchable identifiers
will require an on-going commitment by organizations to providing
persistent access to information objects and their associated metadata.
This commitment must be maintained through budget cuts, changes of
administration, reorganizations, and major changes in technology.

## 4.3 Constraints for Categorization

The constraints identified include the reality that implementing the
categorization of government information starts with the assignment of
responsibility and the accountability for accurate and adequate
performance of the task. The decisions on what is to be categorized will
need to be made and communicated by senior management in order for the
task to be carried out correctly. Likewise, for information to be used
properly by citizens and other government partners, the level of
specificity and completeness will need to be applied consistently across
the government.

Other constraints identified included the volume of legacy material that
may need to be categorized as well as the challenge of integrating
existing materials (and existing categorizations) with materials being
categorized from this point forward. And lastly, the issue of
discrepancies in the way materials are categorized that could create
"false hits" when categorizations are shared across organizations.

# 5. Major Stakeholders

## 5.1 The Public and Non-Government Organizations

The right for the public to have direct access to data and information
resources held by government is a long-standing tenet of public policy
and is codified in laws such as the Freedom of Information Act and the
Privacy Act, among many others. Governments have a responsibility to
facilitate such direct access to the array of mechanisms for data and
information access now being maintained. Agreement on a reasonable
definition of what Government information is to be categorized will
advance meeting this responsibility in a substantial manner.

The various public communities served by governments can obtain
information either directly from government organizations or through
intermediaries. Traditionally, libraries and information services have
played a major intermediary role in public access to government
information, and non-government organizations (NGO\'s) have a similar
stake in government information access mechanisms. Public access to
government information is increasingly being accomplished through public
network facilities such as Web pages and Internet search engines. Such
access is typically regarded as \"dis-intermediated\", although of
course a degree of intermediation is inherent in the choice of
technologies and information selection criteria. 

Consumers of federal information including the general public, business,
academia, state and local governments need to be able to both find
government information as well as evaluate the value of that
information. These information consumers also include foreign citizens
and organizations, as well as professional associations devoted to
information management. These organizations include the American Library
Association (ALA), the Association of Information Dissemination Centers
(ASIDIC), the American Society for Information Science and Technology
(ASIS&T), the National Federation of Information and Abstracting
Services (NFAIS), and the Special Libraries Association (SLA), the
International Council for Scientific and Technical Information (ICSTI),
the International Federation of Library and Museum Associations, the
International Publishers Association, and the Dublin Core Metadata
Initiative. All of these professional bodies have a vested interest in
government's application of standards in its information management
approach.

## 5.2 Libraries and Information Service Providers

Although many people perform casual searching on their own, the
intermediation roles of libraries, information services, and others will
continue into the indefinite future. Much of the nation\'s public
continues to rely on trained searchers and librarians to provide
essential services in access to government information. Public access is
supported by specialized training in library schools and by a massive
and pervasive infrastructure. For instance, the United States has more
than 120,000 libraries, including over 1,250 Federal depository
libraries. 

Online information services (e.g., Lexis/Nexis, Chemical Abstracts
Service, Dow Jones News Retrieval) represent another major community of
practice. These services typically provide fee-for-service search access
and for obvious commercial reasons they have less incentive than
libraries to support open search standards. Yet, online information
services are often major intermediaries for government holdings and most
offer support for the international standard search service adopted by
libraries. The categorization and persistent identification of
government information products supports the value adding to federal
information by these organizations.

## 5.3 Commercial Vendors

The development of information management and retrieval hardware,
software, and integration tools ensures a full suite of tools available
to achieve the requirements of this component. Tangible information
products have traditionally been categorized in library collections
using one of many tools available to manage the information about these
products. We are also seeing the development of a host of tools for
managing similar information about intangible information products. The
requirement for categorization and other descriptive information is key
to the successful implementation of Web Content Management Systems,
"portals" and other methods for managing and retrieving intangible
information products. This requirement responds to the requirement for
good \"precision\" as well as \"recall.\" This requirement will also
support the extension of Internet search technologies to handle
structured information being driven by the requirement for search
interoperability among Internets and within Intranets, i.e., company
internal databases, directories, etc. 

The standards for categorization and identification have been developed
and adopted by a significant number of commercial and non-commercial
private sector entities. These entities include the International DOI
Foundation, CNRI, the Online Computer Library Center (OCLC), the
Department of Defense, the Department of Energy, the Library of
Congress, GPO, and the California Digital Library. In addition,
Microsoft and IBM have championed the development and use of Universal
Description, Discovery and Integration (UDDI). These organizations have
been supported by other international bodies including National and
international standards submitting organizations such as World Wide Web
Consortium (W3C), the National Information Standards Organization
(NISO), and the International Standards Organization (ISO).

Currently, both categorization and persistent identification are
services provided outside of COTS and network applications. However, in
order to achieve maximum effectiveness and utility, both functions need
to become an integral part of both application software and network
infrastructure.

## 5.4 Government Organizations 

The creators of federal information including federal contractors,
grantees, and partners all have a vested interest in how their products
are identified and how they can be located by the public. Likewise, a
similar interest in identifying government information objects is held
by the federal organizations with responsibility for information
infrastructure and information preservation such as the Chief
Information Officers (CIO) Council, the National Archives and Records
Administration (NARA), the GPO's Federal Depository Library Program
(FDLP) and National Bibliography.

Every government organization holds a wide variety of data and
information resources and maintains a wide range of directories and
other data and information locators. Data and information may be in the
form of paper or electronic documents, budget tables, e-mail files,
audio and video files, databases, and data systems of all kinds. These
resources are composed of discrete data elements and such data is only
useful if information about the data element is also readily available.
This kind of descriptive information (sometimes called \"metadata\") is
typically held in yet another resource known as a \"data dictionary\",
\"metadata catalog\", \"repository\", or \"registry\".  Making the
E-Government Act Requirement for categorization functional will require
U.S. Federal Agencies to both apply such "metadata" elements to their
information products as well as make the associated dictionaries,
catalogs, repositories, and registries available for public access.

# 6. Process for Identifying Requirements

We are taking an iterative approach to defining the requirements for the
searchable identification of information. The draft requirements will be
posted online. We will also solicit comments from the major
stakeholders. Finally, we expect to revise the document several times
over the next few months.

The initial version of these searchable identification requirements are
based on a survey of the persistent identification of information
literature, the work of the CENDI Persistent Identification Working
Group, the pioneering Handle and Digital Object Identifier (DOI) work of
CNRI, the Defense Technical Information Center's (DTIC) Handle
implementation experience, and the current DTIC, CNRI, Advanced
Distributed Learning (ADL) Program Office implementation of a virtual
digital learning objects repository.

# 7. Major Requirements

In order for this effort to add value for the public, it should meet
several major requirements. Most importantly, it should enhance access
to government information resources. The public should be able to expect
a set of standard categories to be applied to information released by
government departments and agencies. Government search engines should
provide a predictable level of granularity among search returns from
decentralized data sources without having to know in specific how the
information was categorized. The requirements for categorization must be
compatible with the installed base of existing information
characterization and retrieval mechanisms, many of which represent an
enormous investment of public funds.

## 7.1 Enhances Public Access at All Levels

Public access to Government information can be enhanced by the
requirement for searchable identifiers and categorization if there is
broad buy-in and implementation among the agencies. Even with the scope
limits recommended in this paper, the potential universe of in-scope
resources is vast and rapidly expanding. For the public to use, and
ultimately support through tax dollars, the requirements must be
demonstrable results that make using it worth their while. For the
public, the greatest demonstrable results will accrue from applying the
recommendations to publicly available information. Interagency benefits
from breaking down stovepipes may later accrue from efforts to identify
and categorize non-public or restricted information resources. The
Categorization requirement will need to consider that there are many
customers looking for government information. The recommendation will
attempt to address the expectations within all levels of access; who
customers are; what they are looking for; and what categories will best
support their retrieval approaches. Agencies and Departments may also
benefit from an improved ability to identify and locate
intra-governmental, non-public or restricted information resources.

## 7.2 Equivalent Level of Granularity

A critical mass of information conforming to the identification and
categorization requirement is necessary to achieve wide usage and a
general commitment to the initiative. Acceptance of the categorization
requirements will be enhanced if the information products identified
represent an equivalent level of granularity from one provider (e.g.
Agency or Department) to another. A requirement will not gain broad
support and acceptance if some providers are applying identifiers and
characterization at the journal article level while others are
representing entire databases collectively unless the granularity is
itself a categorization in the requirement. The scope and level of what
products receive identifiers and are categorized, may need to be
mandated in order to achieve a broad based implementation.

## 7.3 Interoperability with other Collections of Information

As already stated previously in this document, same agencies already
categorize their information. These materials include tangible products
that have received bibliographic description and intangible products
that have received metadata description. While these efforts may have
used a variety of different standards, the requirement for
categorization should, to the broadest extent, be able to use this
information as the basis for information under the new standard for
categorizing government information.

## 7.4 Quality Assurance / Consistency

The intent of applying categorization to government information is
primarily to improve the usefulness of the information by giving the
citizen information they can use when evaluating and selecting
resources. If the categorization is not applied consistently or the
quality of the effort is inconsistent, then this goal will likely not be
achieved. In establishing the process of categorization, agencies and
departments should also plan on how they will ensure quality and
consistency in their application of categories. Both manual and
computer-aided categorization can suffer from inconsistent application
or oversight. Training, oversight, and accountability should be
important aspects of the process.

## 7.5 Compatibility with Existing Mechanisms

Defining what public information resources should be categorized must
take into account the existing and developing mechanisms for access. The
approach taken to managing the information created (e.g. metadata)
should be compatible with current legacy systems; be flexible and able
to map to other data structures (covered above); be extensible and able
to add new areas as information changes; and be "open" to integration
with applications that work with indexing, search and other
categorization tools. Some of the legacy systems and integrations that
may be considered include:

-   Direct access to data

-   Library Catalogs

-   Internet Search Engines

-   Government Locators

-   Search Request/Response services

-   Semantic Mapping

These mechanisms are more fully discussed in the "Statement of
Requirements for Search Interoperability."

## 7.6 Application of Searchable identifiers

Searchable identifiers must be globally unique. In other words, the same
identifier will never be assigned to two different resources. The
robustness of the assignment scheme becomes extremely important in a
globally distributed, rather than centralized, environment. The
application of identifiers must support distributed naming and
resolution. Since information is created in a highly distributed manner,
it is essential that any identifier scheme support distributed naming or
identification.

The process of application must support both tangible and intangible
objects. Although the E-Government Act of 2002, Section 207 specifically
addresses intangible information objects, tangible information objects
have a way of becoming intangible information objects without notice.
For example, DTIC is continually converting its microfiche based
technical reports backfile to a digital format. Therefore, it is highly
desirable that the object's identifier support both tangible and
intangible disseminations. The approach to application of identifiers
should utilize an open, extensible architecture. Since persistently
identified objects will exist into perpetuity, the identification scheme
must be open and adaptable to changing technology.

## 7.7 Persistence of Searchable Identifiers 

Once applied, the searchable identifiers must provide persistent access
to digital information objects regardless of the current status of the
organization that created, named, or previously maintained them. In
other words, the requirement must address all aspects of the government
information life cycle, i.e., creation, log-term management and access,
and permanent preservation.

The identifiers should be robust and compatible, to the greatest extent
possible, with existing and emerging persistent identification standards
for intangible and tangible objects. . The searchable identifier scheme
must provide highly reliable access to authoritative information objects
and, where possible, leverage existing and globally unique identifier
schemes, e.g., ISSN, ISBN, UPC, etc.

## 7.8 Use and Function of Searchable Identifiers

Any approach to the application of searchable identifiers must be
scalable in terms of identifier assignment and resolvability.
Ultimately, billions of objects will be persistently identified. In
addition, persistent identification leads to information aggregation.
However, information aggregation is only possible if objects can be
instantaneously resolved and accessed. In addition, the searchable
identifiers themselves should be easy to use. In other words, be
resolvable by the end user with minimal, or ideally no, additional
knowledge beyond the object's name or identifier. In addition, the
process should support multiple machine and user interfaces, e.g.,
browsers and bar code readers. Finally, the identifiers should be human
readable.

The recommendation should support information object metadata to be used
for object discovery, digital rights management, specification of
inter-object relationships, and other services. The use of identifiers
should reference object metadata in an integrated, standard way, e.g.,
users can obtain the metadata of ARK identified objects by appending a
"?" to the object's persistent identifier.

# Appendix 1: Scope of Definition

A. Basis for Definition

Historically several relevant definitions of Government information have
been codified. The narrowest of these definitions is that of "Government
publication" found at **44 U.S. Code 1901, the governing statute for the
Federal** Depository Library Program:

As used in this chapter "Government publication" means informational
matter which is published as an individual document at Government
expense, or as required by law.

This language, derived from the paper documents era, excludes the growth
areas of Federal electronic information. Entire categories of Government
information, such as dynamic data, audio or video files, statistical
data, remote sensing data, and more are ignored by a definition that
emphasizes the fixed "documentary" nature of legacy print products.

Clearly a broader definition is needed. The broadest relevant statutory
definition is that for Federal records, found at **44 USC 3301:**

... "records" includes all books, papers, maps, photographs, machine
readable materials, or other documentary materials, regardless of
physical form or characteristics, made or received by an agency of the
United States Government under Federal law or in connection with the
transaction of public business and preserved or appropriate for
preservation by that agency or its legitimate successor as evidence of
the organization, functions, policies, decisions, procedures,
operations, or other activities of the Government or because of the
informational value of data in them. Library and museum material made or
acquired and preserved solely for reference or exhibition purposes,
extra copies of documents preserved only for convenience of reference,
and stocks of publications and of processed documents are not included.

This language underlies the work of the National Archives and Records
Administration (NARA) safeguarding the records on which the American
people depend for documenting their individual rights, for ensuring the
accountability and credibility of their national institutions, and for
analyzing their national experience. Today more of these records are
being electronically created and maintained than ever before, and NARA
anticipates exponential growth in the number of electronic records to be
maintained and made accessible in the coming years. However, this broad
definition of categorizable information, which includes potentially
billions of email messages and other work products, strains the
boundaries of the ICGI Working Group's charter.

We need to identify a manageable middle ground which, while recognizing
the need to protect national security interests and personal privacy
rights, is sufficiently broad to encompass information dissemination
formats yet to be invented, but focuses on published information. Such
language is found in the **44 USC 3502 definition of public information,
at paragraph 12:**

\[T\]he term "public information" means any information, regardless of
form or format, that an agency discloses, disseminates, or makes
available to the public.

A consequence of adopting this definition could be to exclude from CGI
information products that were produced for an internal agency audience,
but that are also of public interest. This concept is codified in **44
USC 1902, which requires that:**

Government publications, except those determined by their issuing
components to be required for official use only or for strictly
administrative or operational purposes which have no public interest or
educational value and publications classified for reasons of national
security, shall be made available ... for public information.

B. Scope of Definition

The definition of resources to which CGI is applicable excludes
information products about the Government, such as television news
coverage of Government activities, objects owned by the Government, or
owned by other parties and loaned to the Government, such as museum
artifacts The recommended definition will also recognize that Federal
while government information is generally in the public domain, a range
of constraints that may apply to any particular holding.

# Appendix 2: Information on Searchable Identifiers

A. Overview:

The general characteristics of persistent identifiers have been
described in a number of Internet Society Network Working Group Request
for Comments (RFCs), papers, and in the recently published CENDI white
paper "Persistent Identification: A Key Component of an E-Government
Infrastructure\" (see the references). However, except for ARK
identifiers, descriptive metadata is not mandated for persistent
identifier schemes. Nevertheless, effective, real world, distributed use
of identifiers requires additional information beyond the information
object's identifier and location.

Associating metadata with persistent identifiers supports the
distributed creation of value added services such as discovery, the
specification of inter-object relationships, and the aggregation of
information objects to create new information objects, e.g., a
compendium of research papers on a particular subject. By associating
metadata with persistent identifiers, these value added services can be
implemented outside of, and without the knowledge of, existing
organizational 'stovepiped' systems. In addition, associating metadata
with persistent identifiers supports object management, authenticity,
security, and digital rights management.

Finally, associating metadata with persistent identifiers allows the
integration of tangible, non-digital, information objects into the
identifier scheme. For example, a tangible, non-digital, book could be
identified by a searchable identifier. Referencing the book's searchable
identifier might provide both the opportunity to buy the book and the
ability to download it.

B. Persistent and searchable identifier implementations:

A number of persistent identifier schemes, e.g., the Persistent Uniform
Resource Locators (PURLs), Digital Object Identifiers (DOIs), Handles,
and Archival Resource Keys (ARKs), have been developed and deployed. For
example:

-   The Online Computer Library Center (OCLC) developed PURLs. Over
    600,000 PURLs have been assigned by OCLC or partnering
    organizations.

-   The Department of Energy (DOE) has assigned over 141,000 PURLs.

-   GPO was an early adopter and has nearly 50,000 PURLs in use.

-   Over 12 million DOIs have been assigned by International DOI
    Foundation (IDF) registration agencies in the US, Australasia, and
    Europe. The IDF primarily represents commercial publishing
    organizations.

-   The Corporation for National Research Initiatives (CNRI) developed
    and operates the Global Handle System that supports both Handles and
    DOIs.

-   The Defense Technical Information Center has assigned over 125,000
    Handles to its technical reports.

-   The Department of Defense initiated the development of a
    Handles-based virtual repository designed to provide visibility over
    and access to over 10 million digital learning objects.

-   The California Digital Library has assigned over 80,000 ARKs to
    objects it owns or controls.

Although most of these are primarily persistent identification
implementations, increasingly organizations are associating information
object metadata with persistent identifiers to create searchable
identification schemes.

For example, the IDF affiliates, Crossref and Content Directions Inc.,
provide value added DOI services based on information object metadata
called application profiles.

DTIC is developing a system to expose information object metadata and
Handles to the Web to encourage value adding by external organizations.

The proposed ADL virtual repository will combine digital learning object
metadata with Handles to support object discovery and access.

Finally, the ARK identification scheme mandates information object
metadata.

# Appendix 3: Notes and References

Berners-Lee T., Bray T., Connolly D., Cotton P., Fielding R., Jeckle M.,
Lilley C., Orchard D., Walsh N., Williams S. \"Architecture of the World
Wide Web, First Edition W3C Working Draft\", 5 July 2004.
\[http://www.w3.org/tr/2004/wd-webarch-20040705\]

Berners-Lee T., Fielding R., Masinter L. "RFC 2396 -- Uniform Resource
Identifiers (URI): Generic Syntax", August 1998.
\[http://www.ietf.org/rfc/rfc2396.txt\]

CENDI Persistent Identification Task Group, "Persistent Identification:
A Key Component of an E-Government Infrastructure", March 2004.
\[<http://www.dtic.mil/cendi/publications/04-2persist_id.pdf>\]

Daigle L., van Gulik D.W., Iannella R., Falstrom P. "RFC 3406 -- Uniform
Resource Names (URN) Namespace Definition Mechanisms".
\[http://www.ietf.org/rfc/rfc3406.txt\]

Hakala, J. "RFC 3188 - Using National Bibliography Numbers as Uniform
Resource Names", October 2001. \[http://rfc3188.x42.com/\]

Handles System \[http://www.handle.net\]

International DOI Foundation. \[http://www.doi.org\]

Kunze, J. and R.P.C. Rogers. "The ARK Persistent Identifier Scheme"
Internet Draft 31 July 2003.
\[http://www.cdlib.org/inside/diglib/ark/arkspec.pdf\]

Kunze, J. "Towards Electronic Persistence Using ARK Identifiers", July
2003. \[http://www.cdlib.org/inside/diglib/ark/arkcdl.pdf\]

Lynch C., Preston C., Daniel R. "RFC 2288 -- Using Existing
Bibliographic Identifiers as Uniform Resource Names", February 1998.
\[http://www.ietf.org/rfc/rfc2288.txt\]

Markwell, J. and D. Brooke. "Broken Links: Just How Rapidly Do Science
Education Hyperlinks Go Extinct?" 2003.
\[http://www-class.unl.edu/biochem/url/broken_links.html\]

Persistent URLs. \[http://www.purl.oclc.org\]

Sollins K., Masinter L., "RFC 1737 -- Functional Requirements for
Uniform Resource Names", December 1994.
\[http://www.w3.org/Addressing/rfc1737.txt\]

Sun S., Lannom L., Boesch B. "RFC 3650 -- Handle System Overview",
November 2003. \[http://www.ietf.org/rfc/rfc3650.txt\]

\[USC\] United States Code, 2000 edition. Title 44, Public Printing and
Documents, Chapter 19, Section 1901, Definition of Government
publication, available at <http://www.gpoaccess.gov/uscode/index.html>

\[USC\] United States Code, 2000 edition. Title 44, Public Printing and
Documents, Chapter 19, Section 1902, Availability of Government
publications ... , available at
<http://www.gpoaccess.gov/uscode/index.html>

\[USC\] United States Code, 2000 edition. Title 44, Public Printing and
Documents, Chapter 19, Section 3301, Definition of records, available at
<http://www.gpoaccess.gov/uscode/index.html>

\[USC\] United States Code, 2000 edition. Title 44, Public Printing and
Documents, Chapter 19, Section 3501, Definition \[of public
information\], available at <http://www.gpoaccess.gov/uscode/index.html>

\[USC\] United States Code, 2000 edition. Title 44, Public Printing and
Documents, E‑Government Act of 2002, (Paragraph 207(d)(1)) requires that
the Interagency Committee on Government Information (ICGI) submit
recommendations to the Director of the Office of Management and Budget
(OMB) on:

-   "The adoption of standards, which are open to the maximum extent
    feasible, to enable the organization and categorization of
    Government information in a way that is searchable electronically,
    including by searchable identifiers; and in ways that are
    interoperable across agencies;

-   The definition of categories of Government information which should
    be classified under the standards; and

-   Determining priorities and developing schedules for the initial
    implementation of the standards by agencies."