How much overtime did each employee spend donning and doffing? We don't know. Instead, the employees used a statistical analysis to approximate the average time. Per Justice Thomas's dissent, the study "used about 57 employees per activity to extrapolate times for 3,344." The times varied greatly for individual employees. For example, one employee took 35 seconds to put on his gear before his shift, while another took 10 minutes.
A jury relied on the statistical evidence to return a $2.9 million verdict. However, it's tough (impossible?) to tell exactly how the jury came up with that number. The employer argued that people who were not actually injured (i.e. people whose donning and doffing time did not result in working overtime) are not allowed to recover any damages.
Let me paraphrase the holdings:
Employer: The statistical evidence varied greatly from individual to individual and was extrapolated from data for only 1.7% of the employees.
SCOTUS: Meh, close enough. We conclude the statistical analysis "was a permissible means of showing individual hours worked."
Employer: But some of these people didn't work *any* overtime, so they're not allowed to recover! And we don't know which people actually worked OT because... well, see above.
SCOTUS: Yeah, that sounds like a problem for the district court to try to figure out. Good luck with that!
Chief Justice Roberts wrote a concurring opinion, noting his "concern that the District Court may not be able to fashion a method for awarding damages only to those class members who suffered an actual injury."
What is the takeaway for employers? From Justice Thomas's dissent:
The majority thus 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 homogenizes an individual issue.Yeah, employers pretty much have to track any time that could conceivably be compensable... or accept that they might get hammered with statistical analysis from a plaintiff's expert. Sorry if I sound cynical... let's just say I'm skeptical of whether the statistical report really gives us a fair picture of how much time was actually spent by the 3,344 employees.