Auer Deference

Courts defer to an agency’s reasonable interpretation of its own ambiguous regulations, as long as the interpretation is the agency’s authoritative, considered position and not a post-hoc rationalization or plainly erroneous reading.

Elements / Test

Kisor v. Wilkie (2019) — narrowed Auer framework:

Step 1: Exhaust traditional interpretive tools — if regulation is not genuinely ambiguous after applying text, structure, history, and purpose, Auer does not apply; court uses independent judgment.

Step 2 (if genuinely ambiguous): Does the agency’s interpretation qualify for deference?

  1. Authoritative: Reflects the agency’s official position, not just a litigating stance
  2. Not plainly erroneous: Falls within the regulation’s zone of ambiguity
  3. Within delegated authority: Interpretation is of a substantive regulation, not an interpretation of a statute
  4. No unfair surprise: No retroactive application that upsets reasonable reliance

Exceptions and Edge Cases

  • Parroting statutes: No Auer deference when regulation merely repeats statutory text (Talk America)
  • Procedural regulations: Less deference when regulation relates to agency’s own procedures
  • Post-hoc rationalizations: Position crafted for litigation, not agency’s considered policy, gets no deference
  • Nondelegation concerns: Kisor emphasized that Auer applies only when there is genuine ambiguity — prevents agencies from exploiting vagueness they themselves created
  • Legislative vs. interpretive regulations: Auer applies to legislative (substantive) rules, not interpretive rules or policy statements

Policy Rationale

Agency that drafted the regulation understands what it meant; consistency and predictability in regulatory programs; respects agency expertise. Post-Kisor compromise: preserves Auer in limited form while restoring judicial oversight.

Key Cases

CaseRule
Bowles v. Seminole Rock & Sand Co. (1945)Original Auer/Seminole Rock deference to agency’s regulatory interpretation
Auer v. Robbins (1997)Reaffirmed deference to agency’s interpretation of its own regulations
Kisor v. Wilkie (2019)Narrowed Auer; must exhaust interpretive tools first; deference requires authoritative, within-range interpretation

Covered In