In a unanimous decision on February 26, 2008, in the case Sprint/United Management Company v. Mendelsohn, the United States Supreme Court held that a trial court can permit a plaintiff employee to introduce evidence that other employees have also experienced discrimination, provided that the testimony—also known as “me too” evidence—is relevant to the case and its probative value is not substantially outweighed by the danger of its prejudicial effect before the jury. In so ruling, the Supreme Court clarified that “me too” evidence is neither per se admissible nor per se inadmissible but, rather, the trial court must make a determination weighing the evidence's relevance, probative value, and prejudicial effect.

“Me too” evidence can be very problematic for an employer because a trial can degenerate into a situation of mini-trials where employers must litigate numerous allegations involving supervisors and employees who are not directly involved in the plaintiff's own allegations of discrimination. Because the Supreme Court did not establish any bright line standards when this type of evidence is admissible, and instead left it to the discretion of the trial court on a case-by-case basis, employers facing discrimination litigation will continue to face uncertainty whether they will have to defend against this type of evidence in a particular discrimination case.

In the Sprint case, Ellen Mendelsohn was employed in Sprint/United Management Company's Business Development Strategy Group until she was terminated in 2002 in a series of workforce reductions. Mendelsohn, who was 51 at the time of her termination, filed suit against Sprint under the Age Discrimination in Employment Act (ADEA) alleging disparate treatment based upon her age. To prove the discrimination alleged, she sought to introduce testimony of five other former Sprint employees who claimed that their supervisors had also discriminated against them on the basis of their age. None of the five witnesses that Mendelsohn offered at trial were employed in the Business Development Strategy Group with Mendelsohn and none of them had worked under Mendelsohn's supervisors in her chain of command.

Sprint filed a motion in advance of trial to exclude the testimony, claiming that it was irrelevant to the central issue of whether Mendelsohn's supervisors terminated her because of her age. Sprint argued that such evidence would only be relevant if it came from Sprint employees who had the same supervisors as Mendelsohn. Sprint also claimed that, under Rule 403 of the Federal Rules of Evidence, such evidence should be excluded because its probative value is substantially outweighed by the danger of unfair prejudice, confusion of the issues, misleading of the jury, and undue delay.

In its decision in the case, the Supreme Court confirmed that the evidence offered by Mendelsohn was neither per se admissible nor per se inadmissible. Rather, the Supreme Court stated, the admissibility of such evidence is governed by the balancing conducted by district courts between the probative value of the evidence and the danger of its prejudicial effect under Rules 401 and 403 of the Federal Rules of Evidence. Further, the Supreme Court reiterated that the evidentiary inquiry required by the Rules is within the province of the district court in the first instance because the district court is in the best position to make the required fact-intensive and context-specific inquiry. Such decisions, the Supreme Court concluded, should not be disturbed absent a showing of an abuse of the district court's discretion.