The performance and accountability of government agencies and programs have attracted substantial attention by Congress, the executive branch, and others, including GAO. For example, the Government Performance and Results Act of 1993 (GPRA) established a statutory framework designed to provide congressional and executive decision makers with objective information on the relative effectiveness and efficiency of federal programs and spending. A central element of the current administration’s Presidential Management Agenda is the Program Assessment Rating Tool (PART), designed by OMB to provide a consistent approach to assessing federal programs in the executive budget formation process. Over the past 2 years, we have emphasized that the long-term fiscal imbalance facing the United States and other significant trends and challenges establish the need to reexamine the base of the federal government and its existing programs, policies, functions, and activities. We noted that a top-to-bottom review of federal programs and policies is needed to determine if they are meeting their objectives. To support this reexamination, the policy process must have the capacity to provide policymakers not only with information to analyze the performance and results achieved by specific agencies and programs, but that of broad portfolios of programs and tools (including regulation) contributing to specific policy goals. While initiatives such as GPRA and PART can evaluate regulatory performance at the agency or program level, Congress and presidents also have instituted requirements that focus on a more basic element, the agencies’ existing regulations. For example, through Section 610, Congress requires agencies to review all regulations that have or will have a “significant economic impact upon a substantial number of small entities” (generally referred to as SEISNOSE) within 10 years of their adoption as final rules. The purpose of these reviews is to determine whether such rules should be continued without change, or should be amended or rescinded, consistent with the stated objectives of applicable statutes, to minimize impacts on small entities. As discussed later in this report, Congress also established other requirements for agencies to review the effects of regulations issued under specific statutes, such as the Clean Air Act. Every president since President Carter has directed agencies to evaluate or reconsider existing regulations. For example, President Carter’s Executive Order 12044 required agencies to periodically review existing rules; one charge of President Reagan’s task force on regulatory relief was to recommend changes to existing regulations; President George H.W. Bush instructed agencies to identify existing regulations to eliminate unnecessary regulatory burden; and President Clinton, under section 5 of Executive Order 12866, required agencies to develop a program to “periodically review” existing significant regulations. In 2001, 2002, and 2004, the administration of President George W. Bush asked the public to suggest reforms of existing regulations. The Office of Advocacy within SBA and OIRA within OMB have issued guidance to federal agencies on the implementation of, respectively, the RFA and Executive Order 12866. The available guidance documents, including OMB Circular A-4 on regulatory analysis, focus primarily on the procedural and analytical steps required for reviewing draft regulations, but they are also generally applicable whenever agencies analyze the benefits and costs of regulations, including those of existing regulations. However, the documents provide limited guidance focused specifically on retrospective reviews. In a short discussion on periodic reviews of existing rules pursuant to Section 610, the Office of Advocacy’s RFA guidance briefly touches on planning, conducting, and reporting the results of reviews, but the OMB/OIRA guidance does not specifically address the executive order’s periodic review requirement. In our prior work on this subject, we found that agencies infrequently performed certain types of reviews and identified potential challenges and benefits of conducting retrospective reviews. In 1999, we reported that assessments of the costs and benefits of EPA’s regulations after they had been issued had rarely been done. In a series of reports on agencies’ compliance with Section 610 requirements, we again noted that reviews were not being conducted. We identified a number of challenges to conducting retrospective reviews. In general, these included the difficulties that regulatory agencies face in demonstrating the results of their work, such as identifying and collecting the data needed to demonstrate results, the diverse and complex factors that affect agencies’ results (for example, the need to achieve results through the actions of third parties), and the long time period required to see results in some areas of federal regulation. We also identified concerns about the balance of regulatory analyses, because it may be more difficult to estimate the benefits of regulations than it is to estimate the costs. Our report on EPA’s retrospective studies noted that such studies were viewed as hard to do because of the difficulty in obtaining valid cost data from regulated entities and quantifying actual benefits, among other reasons. Our work on agencies’ implementation of Section 610 requirements revealed that there was confusion among the agencies regarding the meaning of key terms such as SEISNOSE, what RFA considers to be a “rule” that must be reviewed, and whether amending a rule within the 10-year period provided in Section 610 would “restart the clock,” among other things. However, our prior work also pointed out that retrospective evaluation could help inform Congress and other policymakers about ways to improve the design of regulations and regulatory programs, as well as play a part in the overall reexamination of the base of the federal government. For example, we reported that retrospective studies provided insights on a market-based regulatory approach to reduce emissions that cause acid rain and that the studies found that the actual costs of reducing emissions were lower than initially estimated. Experts and stakeholders whom we consulted during work on federal mandates (including regulations) and economic and regulatory analyses told us that they believe more retrospective analysis is needed and, further, that there are ways to improve the quality and credibility of the analyses that are done. One particular reason cited for the usefulness of retrospective reviews was that regulations can change behavior of regulated entities, and the public in general, in ways that cannot be predicted prior to implementation. Since 2001, the nine selected agencies conducted multiple retrospective reviews of their existing regulations to respond to mandatory and discretionary authorities. Between 2001 and 2006, the nine agencies reported completing over 1,300 mandatory or discretionary reviews, but many could not tally the total number of reviews that they have conducted. The reviews addressed multiple purposes, such as examining the efficiency and effectiveness of regulations and identifying opportunities to reduce regulatory burden. The mix of reviews conducted—in terms of the impetus to start a review and the purpose of the review—varied not only across but also within the agencies that we examined. Agencies conducted reviews in response to various mandatory requirements, but most agencies indicated that they conducted the majority of reviews based on their own discretion. Agencies reported conducting reviews, at their own discretion, in response to their agencies’ own formal policies and procedures to conduct reviews or to respond to accidents or similar events, changes in technology and market conditions, advances in science, informal agency feedback, and petitions, among other things. Among the main mandatory sources of reviews were governmentwide statutory requirements (such as Section 610 of the RFA or the Paperwork Reduction Act (PRA)), agency- or program-specific statutory requirements (such as Section 402 of the Telecommunications Act of 1996 that requires FCC to review the regulations promulgated under the act every 2 years), Executive Order 12866 on Regulatory Planning and Review (which requires agencies to periodically conduct reviews of their significant regulations), and other executive branch directives (such as the memorandum on plain language). In addition, agencies conducted reviews in response to OMB initiatives to solicit nominations for regulatory reexamination, which were not statutorily mandated reviews or required by a specific executive order, but were a part of executive branch regulatory reform efforts. The frequency of agency reviews varied based on review requirements. In some cases, agencies were required to conduct reviews every 2 years to 10 years. Available information on completed reviews indicated that the numbers of reviews completed by individual agencies in any given year varied from a few to more than a hundred. Agencies’ officials reported they conducted discretionary reviews more often than mandated studies. These discretionary reviews were often prompted by drivers such as informal suggestions or formal petitions from regulated entities seeking regulatory changes, suggestions from the agency personnel who implement and enforce the regulations, departmentwide initiatives to review regulations, or changes in particular technologies, industries, or markets. Although these discretionary reviews were often undocumented, our review of publicly available results for retrospective reviews confirmed that, in some instances, agencies like those within DOL, DOT, and DOJ cited discretionary drivers as the motivation for their reviews. Among the various reasons for agency-initiated reviews, petitions were a major review driver for almost all of the agencies. Agency officials cited three types of petition activities that largely influenced them to conduct regulatory reviews. These petition activities included: (1) petitions for rulemaking where the regulated entities or public requested a modified rule that includes new or updated information, (2) petitions for reconsideration where regulated entities or the public requested that the agency revisit an aspect of the rule, and (3) petitions for waivers where the regulated entities or public requested waivers from regulatory requirements. Some agencies, such as DOT and MSHA, have policies to begin a more formal review of the entire regulation when there are a substantial number of petitions. Agencies also reported conducting reviews in response to various mandatory requirements. However, whether they conducted them more often in response to governmentwide requirements or requirements specific to the policy area or sector that they regulate varied among and within agencies. For example, DOT, USDA’s APHIS, and SBA conducted many mandatory reviews in response to Section 610 requirements, while others, such as EPA and FCC, conducted most mandatory reviews in response to statutes that applied specifically to areas that they regulate. Specifically, all of the mandatory reviews completed by APHIS and SBA since 2001 were conducted in response to Section 610 requirements. Similarly, DOT initiated a systematic 10-year plan for reviewing all of its sections of the CFR in order to satisfy the provisions of Section 610, along with other mandatory review requirements.