In Gross v. FBL Financial Services, Inc., the U.S. Supreme Court held that a plaintiff bringing a claim under the federal Age Discrimination in Employment Act (ADEA) must prove by a preponderance of the evidence that age was the “but-for” cause of the employer’s adverse decision. Distinguishing from Title VII cases, where the burden of persuasion shifts to the employer so long as the employee can demonstrate that discrimination was a motivating factor in an employment decision, Gross holds that under the ADEA, the burden of persuasion remains with the plaintiff at all times.

Mr. Gross, a 54 year-old, was reassigned from his position as Director of Claims Administration to Coordinator of Claims Administration with defendant FBL, and many of his former job duties were transferred to a newly created position occupied by a younger female employee. Gross sued FBL for age discrimination under the ADEA, alleging that the reassignment constituted a demotion that was based on his age. The trial court instructed the jury that Gross had satisfied his burden of proof if he had proven, by a preponderance of the evidence, that age was a motivating factor in FBL’s decision to demote him. The trial court also instructed the jury that FBL had satisfied its burden of proof if it had proven by a preponderance of the evidence that it would have demoted the plaintiff regardless of his age. The jury returned a verdict for the plaintiff, awarding him $46,945 in lost compensation.

A federal court of appeals reversed, finding the trial court’s jury instructions improper under the standard established in Price Waterhouse v. Hopkins. In Price Waterhouse, the Supreme Court held that in Title VII cases, the burden of persuasion shifts to the employer if a plaintiff can demonstrate, by “direct evidence,” that discrimination was a “motivating” or “substantial” factor in the employer’s adverse action. Once the burden of proof has shifted, the plaintiff will succeed in his claim unless the employer can convince the jury that it would have made the same decision regardless of plaintiff’s status in a protected class. The court of appeals held that because the trial court had failed to make the distinction between “direct evidence” and other types of evidence, its burden-shifting instructions to the jury were flawed.

The Supreme Court granted review of the question of whether a plaintiff must “present direct evidence of discrimination in order to obtain a mixed-motive instruction in a non-Title VII discrimination case.” The Supreme Court went beyond the scope of this question, however, holding that the burden of persuasion never shifts to the employer in cases brought under the ADEA. Reasoning that Title VII decisions do not apply to the Supreme Court’s construction of the ADEA, the Court held that a plaintiff alleging age discrimination must prove by a preponderance of the evidence that the adverse employment action would not have occurred but for the plaintiff’s age; at no point does the burden of persuasion shift to the employer.

The decision invited both a harsh dissent from the Court’s liberal wing, and scrutiny from Congress’ Democratic majority, which may seek to amend the ADEA to “undo” the decision. In the meantime, Gross will make it more difficult for plaintiffs to win discrimination claims under the ADEA. The decision does not impact court interpretations of the burdens of proof and persuasion under state law age discrimination statutes.