@Chrchill: OK, if the U of C’s numbers are to be believed (and that’s open to question, as their past behavior has shown):
8% of 28K total = 2240 total admits.
EA & ED1 = 9% of 13K total = 1170 admits in ED1+EA
ED2 & RD = 1070 admits from 15K total.
x * .02 + (15000 - x) * y = 1070
We don’t know how many applied to the U of C ED2 but we do know that roughly the same number applied to ED2 at BU as to ED1. We also know that between 3000 and 4000 apply ED to Brown, Duke, and Northwestern, but the U of C doesn’t have engineering (or a lot of schools that Northwestern has). Between 1500 and 2000 ED to Emory, Dartmouth, and JHU (even though JHU does have engineering). Even being generous, say 2K-4K apply to each of ED1 and ED2 at the U of C.
If 4K ED’ed to each of I and II (and EA had the same 2% admit rate as RD):
ED1: 24.75%
ED2: 21.25%
If 3K ED’ed to each of I and II (and EA had the same 2% admit rate as RD):
ED1: 32.33%
ED2: 27.67%
If 2K ED’ed to each of I and II (and EA had the same 2% admit rate as RD):
ED1: 47.5%
ED2: 40.5%
Note that the school with the most SCEA apps (Harvard) only had a little over 6K, so UChicago almost certainly didn’t have 8K ED’ing to it.
In any case, the U of C is giving a massive bump to those who ED.
It seems like your chances to the U of C range from around 30% to possibly even above 40% if you ED, but they are almost nil if you do not.
And yes, taking in a decided majority of your class in ED most certainly would increase yield.