For those who have a difficult time deciding on whether or not to ED. Here are some things to think about.
If you ED, can you afford it? NPC is all you got to go on so at least you need to look at that.
Do you feel your application is strong enough to get into a top school? (Don't count on perfect stats to get you in)
SCEA/EA does not help you get admitted to top schools (HYPSM), so don't think it will give you a boost like ED
Do any of your top 3 school choices have ED, if so, how close are they in your mind. Close enough that you would just as happy/almost as happy/not very happy at #1 vs #3?
The fact is that there will be many applicants that will be left out, looking at attending whatever safety school they applied to wishing they had applied ED to their number 2 or 3 school.
There are some applicants who will get accepted at there first choice (non ED) school, so if you think that's you, go for it.
This is a tough decision, not so much if your first choice has ED.
If you apply ED for FA but the school doesn’t offer enough aid to support attendance, you tell them thanks but no thanks and apply elsewhere. The school’s NPC will yield a first approximation that usually works well for simple cases (e.g., no self employment, no unusual support issues).
SCEA is fools gold, applicants look at the numbers and think that they triple their chances of getting in but that simply isn’t the case (there are several threads on why this is). AO’s talk about this each year in the fact that they are absolutely sure that anyone admitted in SCEA would have been admitted RD. So you get one thing from SCEA; knowing early if your rejected or accepted and that’s it. Being deferred is the same as applying RD; not going to know anything until the end of March, most applicants will essentially waste their chance at a boost from applying early by applying SCEA/EA.
However, if your decision of where to matriculate requires comparing the FA offer with that of other schools, then ED is not appropriate, since you will (most likely) not have other schools’ FA offers to compare when you have to make the decision to matriculate to the ED school.
“Applying Single-Choice Early Action does not increase the likelihood of being admitted to Yale. Historically, the rate of admission among early applicants has been higher than the overall admission rate because many of our strongest candidates, from a wide range of backgrounds and interests, apply early.”