The Supreme Court’s decision to allow the use of “representative evidence” in Tyson Foods, Inc. v. Bouaphakeo provides guidance when challenging expert testimony.

On March 22, 2016, the United States Supreme Court rejected Tyson Foods, Inc.’s (“Tyson”) request to reverse a $2.6 million judgment entered against it. In the underlying case, hourly employees working in Tyson’s pork processing plant in Storm Lake, Iowa filed a class action lawsuit alleging that Tyson failed to pay them overtime for time spent donning and doffing protective equipment necessary to perform their jobs.

Given the plaintiffs’ allegations, each employee was required to show that he or she worked more than 40 hours a week, including the time donning and doffing protective equipment, in order to recover against Tyson. In order to meet this burden, the plaintiffs offered testimony by their expert witness, who conducted 744 videotaped observations and concluded that it took one set of employees an average of 18 minutes to don and doff their protective gear and a second set of employees an average of 21 minutes to don and doff their protective gear.

The plaintiffs moved to certify a class of more than 3,300 employees who had allegedly been underpaid by Tyson as a result of the required donning and doffing activities. Tyson objected to the motion, arguing that the differences in protective gear each plaintiff was required to wear made the case inappropriate to proceed as a class action. The trial court rejected Tyson’s argument and certified the class.

At trial, Tyson made the same argument to the jury. That is, the varying amounts of time it took employees to don and doff different protective gear made the lawsuit too speculative for classwide recovery. Tyson also argued that the study performed by the plaintiff’s expert overstated the average donning and doffing time. The jury found for the plaintiffs and awarded a verdict of $2.9 million against Tyson.

Tyson appealed the decision to the Eighth Circuit Court of Appeals and then to the United States Supreme Court. Tyson’s primary argument in seeking reversal was that the class of plaintiffs should not have been certified because the primary method of proving injury assumed that each employee spent the same amount of time donning and doffing protective gear, even though differences in the gear may have meant that employees took different amounts of time to do so.

The Supreme Court rejected Tyson’s argument and affirmed the verdict. In doing so, it relied on several factors. First, the Supreme Court noted that the Fair Labor Standards Act requires employers to make and keep records regarding employee wages, hours, and other conditions and practices of employment, which Tyson did not do. The Supreme Court therefore noted that the plaintiffs offered their expert’s study of the average time to don and doff protective gear to fill the evidentiary gap regarding the number of hours they worked created by Tyson’s failure to keep the required records. The Supreme Court also noted that Tyson did not challenge the validity of the expert’s study under Daubert v. Merrell Dow Pharmaceuticals or attempt to discredit the study by offering their own expert.

The Supreme Court’s observations regarding Tyson’s actions prior to and during trial, provide useful guidance when challenging expert testimony. First, if there is an evidentiary gap created by a defendant’s failure to keep required records, it will be difficult to successfully argue that the plaintiffs should be prohibited from offering less precise data to prove their claim. Second, to the extent either party believes that the opposing expert’s testimony is unreliable, a best practice is to file a Daubert motion challenging the admissibility of the testimony as opposed to relying solely on arguments to be presented at trial. Third, if a party desires to challenge testimony provided by the other side’s expert, a best practice is to retain a rebuttal expert to present evidence at trial and to preserve the record for any potential appeal. Indeed, commentary issued by expert witnesses in response to the Tyson decision offers several arguments that could have been presented in response to the study performed by the plaintiff’s expert.

Only time will tell how district courts interpret the Tyson decision. In the meantime, we recommend the best practices identified above when facing expert testimony that you believe is unreliable.