Five years ago, the U.S. Supreme Court seemed to reject the use of statistical proof in class actions, dismissing the evidence as “a novel project.” But, last week, the high court appeared to reverse course. Its new decision, Tyson Foods, Inc. v. Bouaphakeo, is thoroughly enigmatic and contradictory. It will no doubt spawn endless legal battles, and the real estate industry will have to monitor how lower courts struggle to decipher it.

A class of employees sued Tyson Foods over alleged violations of the Fair Labor Standards Act. The workers, who process meat, use heavy protective gear, and the main issue in the lawsuit was a familiar one: whether the time those individuals spend donning and doffing their gear is compensable. Tyson Foods keeps no records about that time, so the plaintiffs came up with an inventive solution. They hired an industrial relations expert to calculate donning-and-doffing averages. A jury embraced that testimony and found in favor of the employees, awarding them $2.9 million in damages.

On appeal, the Supreme Court upheld the jury’s consideration of the expert’s estimates, holding that “whether and when statistical evidence can be used to establish classwide liability will depend on the purpose for which the evidence is being introduced and on the elements of the underlying cause of action.” The test, according to the court, is “the degree to which the evidence is reliable in proving or disproving the elements of the relevant cause of action.” The court correctly anticipated that plaintiffs’ lawyers will greet this decision with unmitigated glee, but the justices nonetheless tried to temper that. “The Court reiterates that while [those groups] may urge adoption of broad and categorical rules governing the use of representative and statistical evidence in class actions,” the majority warned, “this case provides no occasion to do so.”

Whether and when statistical evidence can be used to establish classwide liability will depend on the purpose for which the evidence is being introduced and on the elements of the underlying cause of action. —Tyson Foods, Inc. v. Bouaphakeo

Commentators about the opinion have been abundant, and they have come to varying conclusions. Some view it as a narrow holding; others deem its scope unclear. I would expect judges who are already consumer-friendly to rely on Tyson Foods to justify class actions they would have otherwise certified in its absence. By contrast, less-consumer friendly judges will likely find nothing in this ruling to change their minds. Class-action defendants may be successful in distinguishing the decision by attacking the evidence presented by each individual class member. The employer in this case was evidently unable to do that, in large part because it did not comply with its statutory duty to keep wage-and-hour records.