<p>Here’s a fun application of the analysis: Chicago vs. Northwestern</p>
<p>Each gets about the same number of applications per slot: 8.3. So number of applications doesn’t affect their relative numbers at all.</p>
<p>Northwestern’s gross numbers show an overall acceptance rate of 30% (4,820 out of 16,220 apps) vs. Chicago’s 35% (3,600 out of 10,400 apps). Northwestern’s overall yield is 40.6% (1,950 out of 4,800), while Chicago has an overall yield of 34.7% (1,250 out of 3,600). So Northwestern looks a little more selective, and a little more popular with admittees, notwithstanding that Eastern snobs like me don’t consider it as being anywhere near as attractive as Chicago. (I’m sure no one at Chicago has ever noticed this, or speculated as to why that might be.)</p>
<p>Northwestern, however, takes a little more than a quarter of its class ED from a very small number of ED applications, at a 49% acceptance rate (524 acceptances, 1,079 applications), on which it gets 100% yield. If I estimate that it outright rejects about 10% of the ED pool and defers the rest of the non-admitted EDs, that leaves an RD pool of about 15,600 apps, with 4,300 acceptances, a 27.5% acceptance rate. Out of those 4,300 accepted students, 1,430 chose to attend – almost exactly 33.3% yield.</p>
<p>Chicago gets a lot higher percentage of its applications EA – about 25%, or 2,600 EA apps. Last year, it accepted about 1,150 of those, 44%, but of course they were not committed to attend Chicago. If I make the same assumption about the portion of the EA pool that gets deferred, Chicago’s RD pool would have been about 9,000, of which 2,450 were accepted – 27.2%. And, as noted, Chicago’s yield on all accepted students was 34.7%.</p>
<p>So, it turns out that the apparent difference between Chicago and Northwestern is pretty illusory, and to the extent there is a (slight) difference it goes the other way. Northwestern accepts a (slightly) higher percentage of its early applications, and a (very slightly) higher percentage of its RD applications. Its yield among students who have a choice is slightly lower. The difference between the ED/EA programs at the schools accounts for 100%+ of their apparent differences in acceptance rate and yield.</p>