[URSpider94]

Pragmatically, this conclusion comes from looking at how various demographics do on the SAT, versus how they perform in college after being accepted. Once you establish that this is true (since performance in college is the "ground truth"), then you can go back and look at reasons WHY this happens.

Put another way, the discrimination is the fact, demonstrated by a disparity in prediction vs. outcome. The reasons why this happens are hypotheses.