	Introduction

Many situations have focused congressional attention on the adequacy of the science supporting implementation of the Endangered Species Act (ESA). While most science-based actions under ESA are unchallenged, opponents of some actions under ESA accuse agencies of using "junk science," while others assert that decisions that should rest on science are instead being dictated by political concerns. Legislation to address the use of science in implementing ESA has been introduced in each Congress since the 107 th Congress, but no measures have been enacted. Listings and other actions under the ESA may affect land uses and development. There are multiple examples, such as protecting salmon in the Klamath River Basin or northern spotted owl habitat in the Pacific Northwest, where economic and social disputes have resulted from actions taken to list, protect, and recover species under the ESA. As a result, the protective posture of the ESA and the use of science in its implementation have received renewed attention. The agencies that administer the ESA, the Fish and Wildlife Service (FWS) in the Department of the Interior, and the National Marine Fisheries Service (NMFS) in the Department of Commerce, have procedures and policies in place to ensure the objectivity and integrity of the science that underpins agency decisions. At issue has been how science is used in the ESA processes for listing species, consulting on federal actions, designating critical habitat, and developing recovery plans. This report approaches the issues surrounding "sound science" by discussing (1) controversies over the last decade; (2) the role of science in general—what science is, and what it can and cannot do—as background for assessing the adequacy of science in ESA implementation; (3) the role of science in the legal and policy ESA context; (4) current requirements on the quality and use of information and science by FWS and NMFS; and (5) legislation to address concerns relating to ESA science. Over the years, these distinctions have been controversial in several respects. More recently, lumpers have had the upper hand in the scientific community. However, that tide may be changing. This process is the basis of western science. Section 515 of Appendix C of the Treasury and General Government Appropriations Act for FY2001, generally known as the Information Quality Act (IQA) or the Data Quality Act, directs OMB to (1) issue government-wide guidelines to federal agencies to ensure and maximize the quality, objectivity, utility, and integrity of information disseminated by federal agencies; (2) establish a procedure for people to seek corrections of agency information; and (3) require periodic reports to the Director of OMB of complaints regarding agency information. The ESA does not expressly address this balancing act (and certainly not quantitatively), but considering the strongly protective purpose of the ESA—to save and recover species—and considering the statutory requirement to use the "best scientific ... data available," arguably the ESA intends that all declining species should be given the benefit of the doubt and a margin of safety provided. Science can also play a role in post-listing decisions and procedures under the ESA. For example, scientific information is used in designating critical habitat for listed species. No bills have been introduced to date in the 113 th Congress to amend the ESA. They claim that access to public lands is improved when ESA decisions use peer-reviewed science to protect "truly endangered species."
The adequacy of the science supporting implementation of the Endangered Species Act (ESA) has received considerable congressional attention over the years. While many scientific decisions pass unremarked, some critics accuse agencies responsible for implementing the ESA of using "junk science," and others counter that decisions that should rest on science are instead being dictated by political concerns.
Under the ESA, certain species of plants and animals (both vertebrate and invertebrate) are listed as either endangered or threatened according to assessments of the risk of their extinction. Once a species is listed, powerful legal tools are available to protect the species and its habitat. Efforts to list, protect, and recover threatened or endangered species under the ESA can be controversial. Some of this controversy stems from the substantive provisions of this law, which can affect the use of both federal and nonfederal lands. The scientific underpinnings of decisions under the ESA are especially important, given their importance for species and their possible impacts on land use and development.
The Fish and Wildlife Service in the Department of the Interior and the National Marine Fisheries Service in the Department of Commerce administer the ESA, and each agency has policies and requirements to ensure the integrity and objectivity of the science that underlies ESA decisions. The Information Quality Act (P.L. 106-554, IQA or Data Quality Act) also imposes general requirements and has resulted in agency changes to carry out the goals of that act to maximize the quality, objectivity, utility, and integrity of information disseminated by the agencies.
In several situations, economic and social disputes have resulted from actions taken to list, protect, and recover species under the ESA. Critics in some of these disputes assert that the science supporting ESA actions is insufficiently rigorous. Others assert that in some instances decisions were political rather than scientific. Controversy has arisen over what might be the essential elements of "sound science" in the ESA process and whether the ESA might benefit from clarification of how science is to be used in its implementation. The courts have had occasion to review the use of science by the agencies, which generally must show their decisions were not arbitrary and that they rest on credible science. For some purposes, if that science is the best available, even if it is considered imperfect or incomplete, it still may be used.
Several bills affecting science as used in the ESA were introduced in recent Congresses, but to date none have been enacted. Legislative activity in the 112th Congress is summarized in CRS Report R41608, The Endangered Species Act (ESA) in the 112th Congress: Conflicting Values and Difficult Choices, by [author name scrubbed] et al. No bills concerning ESA and science have yet been introduced in the 113th Congress.
This report provides a context for evaluating legislative proposals through examples of how science has been used in selected cases, a discussion of the nature and role of science in general, and its role in the ESA process in particular, together with general and agency information quality requirements and policies, and a review of how the courts have viewed agency use of science.