## Facts

- Jack Gross, age 54, worked for FBL Financial Services, Inc. and was reassigned in 2003 from “Claims Administration Director” to “Claims Project Coordinator.”
- Gross claimed the reassignment was an age-based demotion because many of his former responsibilities were transferred to a younger employee in her early 40s.
- Gross sued under the Age Discrimination in Employment Act of 1967 (ADEA), which prohibits adverse action against an individual “because of such individual’s age.”
- At trial, the district court, over FBL’s objection, instructed the jury using a Title VII-style mixed-motives framework: Gross could prevail if age was “a motivating factor,” while FBL could avoid liability by proving it would have taken the same action regardless of age.
- The jury found for Gross and awarded $46,945 in lost compensation.
- The Eighth Circuit reversed and remanded for a new trial, concluding the mixed-motives instruction was improper under its understanding of prior mixed-motive doctrine.
- The Supreme Court granted review to determine the proper causation standard and burden of persuasion for ADEA disparate-treatment claims.

## Issues

1. Whether an ADEA disparate-treatment plaintiff must prove that age was the “but-for” cause of the challenged adverse employment action.
2. Whether, in an ADEA case, the burden of persuasion can shift to the employer to show it would have taken the same action regardless of age once the plaintiff shows age was a motivating factor.

## Decision

- The Supreme Court affirmed the judgment ordering a new trial, but on different reasoning than the court of appeals.
- The Court held that an ADEA disparate-treatment plaintiff must prove by a preponderance of the evidence that age was the “but-for” cause of the adverse employment action.
- The Court held that the burden of persuasion does not shift to the employer to prove it would have made the same decision regardless of age, even if the plaintiff introduces evidence that age played some role.
- The Court rejected importing Title VII mixed-motives rules into the ADEA and deemed the district court’s motivating-factor/same-decision instruction inconsistent with the ADEA.

## Legal Principles

- Under the ADEA, “because of” age requires proof of but-for causation: the plaintiff must show the adverse action would not have occurred absent age discrimination.
- ADEA liability cannot be established merely by showing that age was one motivating factor among others.
- In ADEA disparate-treatment cases, the plaintiff retains the burden of persuasion on causation throughout; Price Waterhouse-style burden shifting is unavailable.
- Title VII’s statutory mixed-motives scheme does not apply to the ADEA because Title VII was amended to authorize motivating-factor liability and limited remedies for same-decision cases, while the ADEA lacks comparable text.

## Conclusion

The Court held that ADEA disparate-treatment claims require proof that age was the determinative, but-for cause of the challenged employment action and that the burden of persuasion never shifts to the employer, foreclosing Title VII-style mixed-motives instructions under the ADEA.


Gross v. FBL Fin. Servs., Inc., 557 U.S. 167 (2009)