Thin Rationality Review

Jacob Gersen* and Adrian Vermeule**

Under the Administrative Procedure Act, courts review and set aside agency action that is “arbitrary [and] capricious.” In a common formulation of rationality review, courts must either take a “hard look” at the rationality of agency decisionmaking, or at least ensure that agencies themselves have taken a hard look. We will propose a much less demanding and intrusive interpretation of rationality review—a thin version. Under a robust range of conditions, rational agencies have good reason to decide in a manner that is inaccurate, nonrational, or arbitrary. Although this claim is seemingly paradoxical or internally inconsistent, it simply rests on an appreciation of the limits of reason, especially in administrative policymaking. Agency decisionmaking is nonideal decisionmaking; what would be rational under ideal conditions is rarely a relevant question for agencies. Rather, agencies make decisions under constraints of scarce time, information, and resources. Those constraints imply that agencies will frequently have excellent reasons to depart from idealized first-order conceptions of administrative rationality.

* Professor of Law and Affiliated Professor of Government, Harvard Law School and Department of Government.
** John H. Watson, Jr. Professor of Law, Harvard Law School. For helpful comments, we are very grateful to Judge Harry T. Edwards, Nick Parillo, David Strauss and to participants at a University of Chicago conference on “Federal Agency Decision Making Under Deep Uncertainty,” May 8–9, 2015. Thanks to Evelyn Blacklock, Cindy Guan, and Rauvin Johl for outstanding research assistance.

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