@sbballer, it sounds like you don’t believe H when they say that SCEA provides no advantage. Personally, I believe that it provides little to no advantage at H, Y or P because the SCEA pools are so strong to begin with and contain so many hooked applicants. I think H evaluates its SCEA pool and admits the ones they really want in the knowledge that probably 90% of them will enroll and that most of those won’t even bother to fill out another application. Y & P have almost the same degree of confidence, so also admit a large proportion SCEA of those they know they would admit RD anyway.
The fact that RD rates are now so low perversely boosts that confidence; Y knows that there’s not much chance that they’ll lose an SCEA admit to H, because statistically there’s only a ~3% chance that that applicant will be admitted RD to H in the first place (obviously, it’s actually higher than that because the applicant was admitted to Y, but at such low numbers it starts to get more random) and, anyway, they presumably liked Y better because they applied there early.
What I’m saying is, HYP admit a high proportion of kids early primarily because it gives them greater certainty about who’ll they’ll get, whether it’s quarterbacks, future Fields Medal candidates, development cases or other really, really strong applicants who’ve indicated that they favor the school in question. It doesn’t give a candidate an appreciable boost - it just enables HYP to pick and choose among the best kids who rank them first. The fact that it boosts yield is a bonus for the schools, I think. They’re among the most generous with fin aid anyway, so the fact that a lot of the SCEA admits may be full payers is another thing that’s nice but not the primary driver.
That’s very different from NU and Penn trying to goose their yield/selectivity numbers in order to look more like HYPS, leave their peers like Columbia, Duke and Vandy behind and fine-tune their less-generous fin aid budgets by locking up half the class or more, including kids that might be very strong but likely were long shots for HYPS anyway.
Stanford has historically not wanted to play the game the way NU and Penn play it, and now that they’re clearly among the tippy-tops, they haven’t - so far - seen fit to do things like HYP. As the highest-yielding and most selective school, they don’t need to, either. They take the kids they want SCEA, and the rest RD (because they know the vast majority of their RD admits will accept the offer). As of this year, though, they’re no longer disclosing their SCEA numbers, so things may be changing.