It is well known that the Age Discrimination in Employment Act of 1967 (ADEA) makes it unlawful for an employer to take an adverse employment action against an employee “because of such individual’s age.” On June 18, 2009, the Supreme Court ruled in Gross v. FBL Financial Services, Inc. that the ADEA does not authorize “mixed-motive” claims of age discrimination. Rather, to succeed under the ADEA, an employee must prove that age was the reason, and not just a reason, that motivated the employer’s adverse action.

What is a “Mixed-Motive” Claim of Discrimination?

The premise of a “mixed-motive” claim of discrimination is that the employer took some adverse employment action (e.g., firing or demotion) because of both a permissible reason and an unlawfully discriminatory reason. This type of claim first took hold in discrimination cases brought under Title VII of the Civil Rights Act of 1964, which prohibits discrimination on the basis of race, color, religion, sex, or national origin. The Supreme Court interpreted Title VII to authorize mixed-motive claims of discrimination under that statute.1 In such cases, the employee bears the initial burden of showing that the employee’s membership in a protected class played “a motivating part” in the adverse employment decision. If the employee meets this burden, the employer may avoid liability only by proving that it would have made the same decision even if it had not considered the unlawful factor.

In 1991, Congress amended Title VII to expressly state that an unlawful employment practice occurs when race, color, religion, sex, or national origin “was a motivating factor for any employment practice, even though other factors also motivated the practice.” This amendment confirmed that “mixed-motive” liability was recognized under Title VII.2

Over time, courts have likewise permitted employees to assert “mixed-motive” claims of age discrimination under the ADEA. In doing so, the lower courts relied upon the Supreme Court’s long-held position that its interpretations of Title VII apply in the context of age discrimination under the ADEA. In a 5-4 decision in Gross, however, a majority of the Supreme Court interpreted the ADEA differently.

Facts of Gross and the Lower Court Decisions

After three decades of employment with FBL Financial Services, Jack Gross was reassigned to a different position at the age of 54. Many of his job responsibilities were given to a younger employee who had previously been supervised by Gross. Gross sued his employer for age discrimination under the ADEA, alleging that his employer demoted him at least in part due to his age.

At trial, the court instructed the jury that if Gross proved that he was demoted (e.g., an adverse employment action) and his “age was a motivating factor” in the demotion decision, the jury should find for Gross. The court told the jury that age would qualify as a “motivating factor” if it played a part in the demotion. The court further instructed the jury to find for the employer if the employer proved that it would have demoted plaintiff regardless of his age.

The jury returned a verdict for the employee. The employer challenged the jury instructions on appeal. The appellate court found the instructions to be faulty and remanded the case back to the trial court for a new trial. Gross appealed this ruling to the U.S. Supreme Court.

The Supreme Court’s Decision

The Supreme Court observed that the ADEA’s text, unlike Title VII, does not authorize mixed-motive claims of age discrimination. Specifically, the ADEA does not provide that a plaintiff may establish discrimination by showing that age was simply “a motivating factor.” Rather, the Court concluded that a plaintiff must prove that age was the “but-for” cause of the employer’s action.

Under a “but-for” analysis, the question is: “But-for the employer’s consideration of the employee’s age, would the employer have taken the adverse employment action?” If the employee proves that “no” is the answer to this question, the employee has proven unlawful age discrimination under the ADEA. If the employee fails to make this proof, the employee has failed to prove age discrimination under the ADEA. In either case, the burden of persuasion that age was the determining factor always remains on the employee.

The Court found the 1991 amendments to Title VII, which expressly allow for mixed-motive claims, to be irrelevant to the ADEA analysis. Because Congress did not amend the ADEA in similar fashion despite making other amendments to the ADEA at the same time, the Court concluded that the textual differences between Title VII and the ADEA precluded a finding that Congress meant to allow “mixed-motive” liability under both statutes.

Implications for Employers

The Court’s imposition of a “but-for” causation test on ADEA claims is significant. This standard will make it more difficult for employees to succeed under that statute.

Yet, the Court noted that whether liability “should” exist under the ADEA when age plays any role in an employer’s adverse employment action “is a decision for Congress to make.” Employers must stay tuned to see whether Congress responds to the Court’s ruling in Gross by amending the ADEA to include express language permitting an employee to bring a mixed-motive claim of age discrimination and lower the burden of proof necessary for a plaintiff to prevail on an age discrimination claim.