Evaluating agency use of 'best available science' under the Endangered Species Act

Since Congress passed the Endangered Species Act (ESA) in 1973, the world's population has nearly doubled, environmental issues have become increasingly politicized, and species continue to go extinct at alarming rates, leading to political conflict that potentially impedes ESA implementation. Because the ways in which agencies use science in the ESA often serve as the legal basis for litigation, it is timely and pertinent to evaluate the quality of science used, both in order to point to ways of improving ESA science policy and to minimize agency exposure to future litigation. The "best" available science and its use are each moving targets, difficult to define in the abstract. However, a straightforward way of evaluating these ideas is to compare the use of science by each of the two administrative agencies in charge of implementing the ESA, the Fish and Wildlife Service (FWS) and the National Oceanic and Atmospheric Administration's National Marine Fisheries Service (NOAA). Here, I use a suite of data sources---including litigation records, authorship affiliation, and bibliography and listing frequency data---to ask whether one agency systematically uses "better" science than the other. I find that the NOAA outperforms the FWS on four of eight metrics, while the agencies do not differ by the remaining four metrics, suggesting that, overall, the NOAA uses systematically better science than FWS. Lastly, I interpret my findings in the context of each agency's budget, structure, and history and highlight specific policy mechanisms that would allow the agencies to use better science and improve endangered species management.