[notakio]

In this case (Lejeune vs Pendleton), there would likely not be a substantial socioeconomic difference between the collective backgrounds of Marines who did basic training at either one. But comparing either camp to OCS at Quantico would, in fact, show a pretty stark delineation between the socioeconomic backgrounds.

[pmoriarty]

There might not have been much difference between them at the time, but who knows how their lives went after their time there?

Some might have wound up being relatively wealthy compared to the rest, and that could have influenced their long-term health.

We won't know until we check.

[alistairSH]

They looked at officer vs enlisted, which would cover any socioeconomic difference between basic vs OCS, no?