This stat is pretty much always just a direct comparison between grads, right? I wonder how different it would be if you took into account confounders like econ

This stat is pretty much always just a direct comparison between grads, right? I wonder how different it would be if you took into account confounders like economic class. I assume much of the widening is college becoming standard, and therefore the only people who don't attend are those who either can't and are disadvantaged in general or those who don't feel particularly ambitious about their career