Courts rhetorically acknowledge that they lack the technical and substantive expertise possessed by executive-branch agencies. Accordingly, courts have designed administrative law doctrines around the idea of deferring to agency expertise. In Chevron U.S.A. Inc. v. Natural Resources Defense Council, the Supreme Court acknowledged, “Judges are not experts in the field. . . . When a challenge to an agency construction of a statutory provision, fairly conceptualized, really centers on the wisdom of the agency’s policy, . . . the challenge must fail.” Attitudinal models of judicial behavior, however, predict that these doctrines fail to meaningfully constrain judicial ideology. Using new data of over 4,000 decisions issued by the U.S. Circuit Courts of Appeals from 1994 to 2020, we test the relationship between ideological congruence, administrative expertise, and deference to agency interpretations of law. The data includes policy decisions made by over 250 agencies across five presidencies, allowing for analysis of ideological congruence at both the agency and presidential level. We conclude with a discussion of what our results suggest about the future implementation of the Supreme Court’s decision in Loper Bright v. Raimondo.

A version of this paper has been accepted for  presentation at 2025 annual meeting for APSA in September.