Let me just throw one thing out there, to raise some speculation: While it's true that experience is positively correlated with productivity, this might operate differently in the minimum wage sector. There, I bet 2 years of experience might be as good as 10 - there's not a lifelong learning curve like in more high-skilled industries - so an employee might "plane out", productivity-wise, after 2 years of experience. If that's the case, then older employees aren't categorically better, as they don't have productivity gains in the future that the employer could benefit from. Younger workers still would have these gains in the future. So, if younger and older were about on par productivity-wise, then it would make sense for the employer to keep the younger worker, who has the possibility of future gains from experience, and lose the older worker, who has already planed out. ~fischer