Can plaintiffs use statistical models based on a sample of plaintiffs to establish that a bigger group of people has been harmed?
This case touches on one of the biggest clashes over class actions: Do they allow people with similar legal complaints to get the justice they deserve, or do they make it too easy for plaintiffs to mount a case?
The case before the Supreme Court is Tyson Foods v. Bouaphakeo. Hourly workers at a Tyson Foods meat processing plant said they were not adequately paid for the time they spent walking to their work stations and changing into protective gear.
The plaintiffs used some actual time sheets and "representative" evidence as proof of their financial damages. Tyson argued there were too many differences among the workers to constitute a true class. The Supreme Court heard arguments in November.
Legal 'standing' to bring lawsuits
How much 'harm' must a plaintiff show to bring a lawsuit in the first place?
It's a basic rule that you can't get through the courthouse door if you can't show you have been harmed in a concrete way. That's one of the factors that gives someone "standing" to bring a suit in federal court.
In Spokeo Inc. v. Robins, the Supreme Court is mulling whether a "bare" violation of a federal law can be enough to let someone sue -- even without showing tangible harm.
The case was brought by a man who says a credit agency was reporting inaccurate information about him, in violation of the Fair Credit Reporting Act. It was argued before the Supreme Court in November.
Related: Washington digs in for a Supreme Court fight
--CNN's Ariane de Vogue contributed to this report.