The Battle Over Endangered Species Act Methodology

50 Pages Posted: 18 Sep 2003 Last revised: 21 Dec 2008

J. B. Ruhl

Vanderbilt University - Law School


The substantive contours of the Endangered Species Act (ESA) have been largely worked out for quite some time. Starting in the mid-1990s, however, opponents of Fish and Wildlife Service and National Marine Fisheries Service decisions from both the industry and the environmental group corners realized that the methodological contours of the ESA were not nearly as settled as their substantive kin. Thus a frenzy of ESA methodology debate materialized in the late 1990s and has been going strong since then, reflecting the realization industry and environmental interests must have made - that how these methodological rules get worked out could revolutionize the ESA for decades to come. This Article explores the breadth and depth of the ensuing battle over ESA methodology. It begins by laying out a framework for evaluating decisionmaking methodologies. One basis on which we might choose how to go about making decisions is what level of confidence we wish decisions to enjoy. Also, how we frame the hypotheses to be tested will influence who favors which methodology. And methodology selection also has much to do with aversion to mistaken conclusions about whether the hypothesis is true.

Because methodology selection depends so much on how hypotheses are stated and the risk aversion bias of different interest groups, the Article next provides some background on the ESA and its numerous decisionmaking nodes - the points at which a choice among the three methodologies must be made using one or more of the frameworks discussed above. Three features of the ESA make its decisionmaking context particularly susceptible to fights over methodology. First, many decisions the agencies must make involve questions of biological science for which the available scientific database is either sparse or inconclusive. Second, these biological evaluations often arise in legal contexts that present a poor fit between science and policy. Finally, ESA decisions are characterized by the intense involvement of viciously combative interest groups willing to sue each other and the agencies with what appears to be gleeful abandon. Where the opportunity presents itself to shape ESA methodology, the opposed interest groups seem happy to litigate to a pitched battle in short order.

Next the Article frames and assesses the battle positions, which fall into three competing methodological camps I call the Professional Judgment Method, which is the default rule for the ESA, and its two postulated alternatives, the Scientific Method and the Precautionary Principle Method. These three methodologies incorporate starkly different approaches to management of risk relating to species conservation. Yet, close examination reveals neither of the postulated alternatives to the Professional Judgment Method finds support in the statutory framework of the ESA.

Nevertheless, there are times when the Scientific Method and the Precautionary Principle Method have a role to play under the ESA, sometimes even hand-in-hand. The challenge is to design a framework that both gives them a role and keeps them under control. The final section of the Article outlines a proposal to create a procedure under which FWS and NMFS could elect to adopt the precautionary principle in discrete decisionmaking instances based on a finding that a significant risk of error with severe consequences exists in connection with a decision not to extend protection to a species. Any interested person could then require the agency to obtain a rigorous scientific peer review of the basis for the agency's decision as means of checking against irrational precaution. Conversely, the proposal would also establish a process under which any interested person could petition a standing committee of scientists to decide whether require a scientific peer review upon finding that the agency may have failed to elect the precautionary principle when it should have under reasonable precautionary guidelines. To guard against overuse of either procedure, the results and findings of the peer review would be entitled to great deference in any judicial review proceeding of the agency's final decision. This would leave the Professional Judgment Method in its appropriate position as the default methodology for ESA decisions, but allow the Scientific Method and Precautionary Principle Method a role in difficult cases.

Suggested Citation

Ruhl, J. B., The Battle Over Endangered Species Act Methodology. FSU College of Law, Public Law Research Paper No. 99. Available at SSRN: or

J. B. Ruhl (Contact Author)

Vanderbilt University - Law School ( email )

131 21st Avenue South
Nashville, TN 37203-1181
United States

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