## Facts

- Knolls Atomic Power Laboratory (Knolls), a contractor operating a federal research facility, was directed to reduce its workforce for fiscal year 1996.
- After a voluntary buyout, Knolls implemented an involuntary reduction in force (RIF).
- Managers selected employees for layoff using a scoring system based on subjective criteria—performance, flexibility, and critical skills—plus additional points for years of service.
- Of 31 salaried employees laid off, 30 were age 40 or older.
- Laid-off employees sued under the Age Discrimination in Employment Act (ADEA), alleging disparate treatment and disparate impact; the disparate-impact claim focused on the age-skewed results of the scoring criteria.
- Plaintiffs presented statistical evidence that the outcomes were unlikely by chance and that the most discretionary criteria correlated most strongly with layoff selection.

## Issues

1. In an ADEA disparate-impact case, who bears the burdens of production and persuasion on the statutory defense that the challenged practice was based on “reasonable factors other than age” (RFOA) under 29 U.S.C. § 623(f)(1)?

## Decision

- The Supreme Court vacated the judgment for the employer and remanded.
- The Court held that RFOA is an affirmative defense, and the employer bears both the burden of production and the burden of persuasion to establish it.
- The Court rejected the view that the plaintiff must prove the employer’s non-age factors were unreasonable once disparate impact is shown.

## Legal Principles

- Once a plaintiff establishes a prima facie disparate impact under the ADEA, the employer may avoid liability only by proving the practice was based on “reasonable factors other than age” within § 623(f)(1).
- Statutory exemptions framed as conduct that “shall not be unlawful” function as affirmative defenses; the party invoking the exception bears the burden of proving it applies.
- The ADEA’s RFOA standard is less demanding than Title VII’s “business necessity,” but that difference does not shift the burden of persuasion to the plaintiff.
- The ADEA’s incorporation of Fair Labor Standards Act enforcement mechanisms supports placing the burden of proving exemptions on employers.

## Conclusion

The Court allocated the burden of proof for the ADEA’s RFOA clause to employers, requiring them to both raise and persuade the factfinder that a practice causing age-based disparate impact was justified by reasonable non-age factors.


Meacham v. Knolls Atomic Power Lab., 554 U.S. 84 (2008)