Actually, I should have been specific: you see disadvantages related to ethnic group down the line. If a group has a lower SAT score, they generally have the same gap on the LSAT, GRE, GMAT etc.
This is heavily related to socioeconomic status in the US. IIRC, in the UK for example you don't see these same gaps between ethnic groups. So it's something specific to US social circumstances, and not racial.
I don't know so much about particular circumstances, I just know what the high level stats say, and am inferring from that. I'm not American, so I don't have lived experience of the class structure there.
There are probably studies about income, but the test makers tend to only collect official data about ethnicity. It's commonly used as a proxy for social class, but I wish the test makers had better data about the elements the College Board is trying to capture with this new policy.
It's about one standard deviation between high scoring groups and low scoring groups across the tests.
LSAC no longer has theirs posted publicly, but it was much the same.
So, to the extent ethnicity is a proxy for social class in the US, we can say that the disadvantage these groups have at SAT time doesn't vanish by the time they take graduate level exams.
I wish I had some data for you that was based on social circumstances other than race, but I don't have deep knowledge in the domain, only what I've seen looking at the reports produced by the test companies recently.
Can you say more about this? Do students who (presumably) leave home to go to college still have as-significant challenges after? How so?