@marlowe1 It’s not particularly a valid form of argument to demand statistics that will never be available as proof of something that can be proved by inference many other ways.
One of the features of ED at the elite level is that, for colleges that can afford to give a lot of aid (but not unlimited aid), its structural features obviate the need to practice actual discrimination in aid packages. ED skews wealthy without any intervention by the college, for several reasons:
ED is especially attractive to kids who are sophisticated about college admissions, who have evaluated their college choices early in their senior years, who go to schools where lots of other kids apply ED and counselors recommend it, and who do not feel a need to compare financial aid offers from various schools in order to make certain they are getting the best financial deal.
Every one of those features select for wealthier applicants. Sure, a really sophisticated non-wealthy kid can decide he or she will get a good enough deal from ED to make it worth applying, and some do, But those kids (and their parents) will hear a chorus of naysaying peers telling them that ED is only for the rich or for those so poor that no college will expect them to pay for anything. (Check out financial aid discussions on CC, and you will see that opinion expressed time and again.) Many colleges – not including the University of Chicago – do in fact award less favorable aid/merit packages to ED applicants, whom they do not have to compete with other colleges to enroll. That contributes to the general anti-ED folklore in the middle classes. So at the end of the day, the ED pool is a lot wealthier than the RD pool. If you treat the applicants all equally, you are going to admit a reliably wealthier class if you do it ED.
I would have pointed you to The Shape of the River, by William Bowen (former president of Princeton) and Derek Bok (twice former president of Harvard). It’s a long discussion of college admissions and social justice, and argues very strongly against early admissions programs of any type based on their race- and class-discriminatory effect. The authors believed in their thesis so strongly that when Bok became president of Harvard for the second time, after the book had been written, he made a real attempt to end early admissions. Harvard and Princeton terminated their respective SCEA and ED programs, only to resume early admissions three years later after they failed to convince any peer universities other than UVa to join them. (And it was clear they were taking a hit in the admissions arena, especially Princeton.)
No one ever suggested that either Harvard or Princeton was discriminating against early acceptees in their financial aid packages. That wasn’t anywhere near enough, in the eyes of their former presidents, to make their early admissions programs nondiscriminatory.
So, yes, another argument from authority. But they are damn good authority on the issue of the effect of admissions practices on the composition of college student bodies.
Note that this does NOT assume that colleges are choosing ED for financial reasons. Harvard and Princeton resumed early admissions purely because they were demonstrably losing out on students they wanted to enroll. Neither was in any financial difficulty, to say the least. Harvard’s yield went down about 10 percentage points during that period, and Princeton (which had previously admitted half of its class ED) saw its yield decline much more than that, threatening its ultra-elite image.
(It’s completely disingenuous, by the way, to suggest that financial considerations don’t loom large in making ED popular for colleges. Maybe not so much for Chicago, which looks financially weak only in comparison to a handful of other elite universities, but definitely for the many colleges that want to say they are need-blind (or 90% need blind), but can’t afford to go over their financial aid budget and need to make certain they don’t. That is what Vice Presidents for Enrollment Management and Financial Aid do; that’s their job.)