Caltech is infamous for focusing on stats. Factors like legacy status, affirmative action, recruited athlete status, etc. play a very limited role. There was an outcry when I was in high school because Caltech did not have a single black student in its freshman class, and Caltech currently has only 14 black students out of 979 undergraduates.
Test scores seem to track very closely with admissions results at Chicago. It’s one factor that has helped it climb in the rankings (test scores are ~8% of the ranking).