Data indicate the importance of expert agencies in conservation policy.

AO_SCPCAPBSTRACTC_SCPCAPData on the implementation of laws and policies are essential to the evaluation and improvement of governance. For conservation laws like the U.S. Endangered Species Act (ESA), such data can inform actions that may determine the persistence or extinction of species. A central but controversial part of the ESA is section 7, which requires federal agencies to conserve threatened and endangered species. One way they do this is by consulting with expert agencies for the ESA, the U.S. Fish and Wildlife Service (FWS) and the National Marine Fisheries Service (NMFS), on actions they may undertake that impact listed species. Using data from all 24,893 consultations recorded by NMFS from 2000 through 2017, we show that federal agencies misestimated the effects of their actions on listed species in 21% of consultations, relative to the conclusions reached by NMFS. In 71% of these cases the federal agency underestimated the effects of their action. Those discrepancies were particularly important for the conservation of 14 species in 22 consultations, where the agency concluded that its action would not harm a species, while NMFS determined the action would jeopardize the species existence. Patterns of misestimation varied among federal agencies, and some of the agencies most frequently involved in consultation also frequently misestimated their effects. Jeopardy conclusions were very rare--about 0.3% of consultations--with a few project types more likely to lead to jeopardy. These data highlight the importance of consultation with the expert agencies and reveal opportunities to make the consultation process more effective.\n\nSO_SCPCAPIGNIFICANCE STATEMENTC_SCPCAPThe US Endangered Species Act is the strongest environmental law any nation has enacted to conserve imperiled species. However, policy debates over how the Act should be implemented continue to this day. This study provides the first comprehensive evaluation of how the National Marine Fisheries Service (NMFS) implements one of the Acts most important conservation programs - consultations under section 7. Our results reveal novel insights into the importance of NMFS role in ensuring federal actions do not jeopardize the existence of listed species. By using data to inform policy debate, we identify approaches to implementing section 7 that would undermine the conservation of imperiled species, and those that could improve the efficiency of the program without sacrificing these protections.