SCEA deferred vs rejected

So I understand the principle of the three outcomes of SCEA:
accepted (for students who are above the average yalie and top of the rigorous pool)
deferred (maybe they’ll get in with RD)
rejected (nope)
But I’m wondering if anyone has insight in terms of rejected vs deferred. Do they only reject people who there is no way they would work for yale and defer all the candidates that they cannot easily accept or do they go through a fine tooth comb and reject a lot of decent candidates as well the same way they do in RD? (This is not meant to insult anyone; obviously 99.9% of yale applicants are fantastic students)
Thank you!

Yale tends defer percentages similar to many of its peers. Stanford notably rejects many in the EA round. Yale rejects roughly 1/4 (decent or not) whom they feel won’t be competitive in comparison to the RD pool.