On Tuesday, the U.S. Supreme Court affirmed a lower court decision that found Tyson Foods liable for an almost $5.8 million damage claim regarding overtime pay for time spent donning and doffing protective equipment in an Iowa pork processing plant.

Workers at the plant, which employs about 1,300 people, sued in 2007, claiming they were entitled to overtime pay and damages because they were not paid for time spent donning and doffing and walking to their work stations.

The court, in a 6-2 ruling written by conservative Justice Anthony Kennedy, upheld a 2014 appeals court decision in favor of the workers. In a federal district court trial in Iowa in 2011, the jury sided with the workers.  The case, to recover overtime pay from Tyson Foods, was brought as a “collective” action under the Fair Labor Standards Act but as a “class action” under state law.

In Tyson Foods, Inc. v. Bouaphakeo, the court considered an objection to the use of statistics to determine liability and damages.  Tyson’s argued it was not proper to permit the employees to pursue their claims as a class because the primary method of proving injustice assumed each employee spent the same time donning and doffing protective gear, even though differences in the type of gear may have meant that employees took different amounts of time to put on and take off their various gear.

No time records were kept by the company to record the time each employee spent donning and doffing.  So to proof their case, the plaintiffs used what was called “representative evidence,” including employee testimony, video recordings of donning and doffing, and a study performed by an industrial expert hired by the plaintiffs.

The industrial expert conducted 744 video-taped observations and analyzed how long various donning and doffing activities took.  Those activities were then averaged to produce an estimate on the time it took to put on and take off  equipment and to estimate the amount of uncompensated work each employee did.

Tyson Foods was critical of the use of those statistics maintaining that it violates defendants’ due process rights, instead of assessing each claim individually for the more than 3,000 current and former employees who are suing the company.  Tyson objected also on the wide variations in how long the extra work took and also that some workers were not entitled to overtime at all.

Justice Kennedy wrote that statistical proof was sufficient.  He also said that the workers should not suffer because Tyson failed to keep records, citing a 1946 Supreme Court precedent “where the employer’s records are inaccurate or inadequate and the employee cannot offer convincing substitutes, the Court said in 1946, it is enough for workers to rely on “sufficient evidence to show the amount and extent of that work as a matter of just and reasonable inference.”

Justices Thomas and Alito, in dissent, wrote the statistical approach “puts employers to an untenable choice.”  “They must either track any time that might be the subject of an innovative lawsuit or they must defend class actions against representative evidence that unfairly homogenized an individual issue.”

The money awarded  in the case has not yet been distributed to the workers.  The Supreme Court said Tyson is free to challenge payments to workers who were not eligible for overtime.