I think colleges will lean on their regional admissions reps and enrollment management staff.
They know the schools in their territory and I am sure that there is some longitudinal data regarding demographics (which will not radically change). There will be data that tells them, that if students are accepted from high school “A’, what is the retention and graduation rate for those students.
I think that schools who have built relationships with colleges and have delivered students will have an easier time of assessing and advocating for their students.
This may also carry over to programs like Posse, QuestBridge and college access programs like SEO, TFI, bottom Line, College Map, etc.
I am in NYC and they had SAT school day on March 4 where the city paid for all public school juniors to take the SAT and for Sophomores to take the PSAT. Hopefully students will have a baseline. The PSAT scores can be used for College Now (seniors who participate junior and senior year will, be able to submit their college transcripts along with their HS transcripts).