<p>^I believe that the ED pool, in general, is slightly weaker than the RD pool. I think there may be some statistical evidence to back this up, but I’m not sure. In any case, this is usually explained away by tipped athletes; but that doesn’t explain a higher admit rate for EDII in comparison to RD. </p>
<p>I agree that ED pools will be self-selecting–but in the other direction. More full-pay students because they don’t have to worry about FA, and more borderline students who want the admissions boost. The best student, ranked 8 or 9, are likely to pass up ED at a school like Swarthmore because they want to see admissions results from HYPS (none of which have binding early programs).</p>
<p>So let’s say that the RD median score is 5 and the ED median score is 4. For simplicity’s sake, I’m going to discuss only the EDII pool because this will eliminate most recruited athletes and development admits. The college accepts 6-9, with preference for 7+. (This is exactly the same as your scenario except that I’m playing out the lower ED pool.) 8s and 9s are essentially auto-accepts in the ED pool, but there simply aren’t that many of them who make the early commitment. 7s are also, for the most part, accepted. But I believe that some 6s will be accepted as well–not the ones with low grades, but perhaps with less-than-perfect test scores or “ordinary” ECs or some other not-so-fatal flaw–because the college knows that it has to admit 45-50% total through ED, and let’s take a wild estimate of 20% through EDII (my thread from last year on Swarthmore’s EDII admit rate could be useful, if anyone wants to run real numbers).</p>
<p>The RD admit rate is around 16%, EDII around 25%–but the EDII pool is weaker or at best equal. Wealthy full-pay applicants also tend to be strategic and will apply ED to true reaches (though not high reaches), so I don’t see any reason why the ED pool would be stronger. Hence, admissions has to reach deeper into the EDII pool in order to reach its target “locked” enrollment.</p>
<p>In the RD round, the college focuses on yield by taking interest into account. However, I don’t think that most colleges will reject “overqualified” applicants; instead, they try to woo them. In fact, by admitting half the class through ED, Swarthmore has set itself up to deal with a low RD yield. All the 8s and 9s will still be admitted, but most of them won’t attend. 6s and 7s are more likely to attend–but they aren’t better than the 6s and 7s who were picked up in ED. So instead of admitting borderline cases in RD for yield, the college could (I speculate, of course) choose to admit borderline cases in ED for near-perfect yield and accept a very low RD yield on only highly desired applicants. After all, the final yield rate that matters is not RD, but overall.</p>
<p>Moreover, I believe that ED is an institutional priority because–aside from hedging enrollment variations–it also benefits the college to have a portion of its student body guaranteed to be enthusiastic about attending their first choice. And, knowing that the RD pool will be stronger than the ED pool, if a college accepts as deeply as necessary in order to preserve yield, it can focus on admitting only the applicants that it truly wants during RD.</p>