<p>Yes, it includes ED admits.</p>
<p>Let’s say a school has a class size of 2000, and they admit 1000 ED. Now, in order for them to have a yield of 60%, they have to have accepted 3333 students. Since 1000 were accepted early, that’s 2333 in the RD round, of which 1000 have to accept the offer. The yield for RD would be 43%, not 10% as you suggest.</p>
<p>But let’s look at some real stats, because schools do not usually accept 50% of the class ED. Some schools are creeping closer towards that line, but most are closer to the 40% range. Here are 2 schools with ED, using the admit stats from the class of 2016.</p>
<p>Duke</p>
<p>Duke admitted 648 students early for a class of 1705. (Source: [Duke</a> admits 648 early decision applicants | The Chronicle](<a href=“http://www.dukechronicle.com/articles/2011/12/15/duke-admits-648-early-decision-applicants]Duke”>http://www.dukechronicle.com/articles/2011/12/15/duke-admits-648-early-decision-applicants)) So, they only filled up 38% of the class early.</p>
<p>They admitted 3105 students in the regular round. (Source: [Duke</a> accepts 11 percent of regular decision applicants for the Class of 2016 | The Chronicle](<a href=“http://www.dukechronicle.com/articles/2012/03/29/duke-accepts-11-percent-regular-decision-applicants-class-2016]Duke”>http://www.dukechronicle.com/articles/2012/03/29/duke-accepts-11-percent-regular-decision-applicants-class-2016))</p>
<p>That means they are expecting 1057 of the 3105 regular admits to accept a place in the freshman class, which is 34%. However, they did accept a further 170 from the wait list, so the yield was closer to 28% = (1057 - 170) / (3105). (Source: [Admissions</a> yield drops two points | The Chronicle](<a href=“http://www.dukechronicle.com/articles/2012/07/02/admissions-yield-drops-two-points]Admissions”>http://www.dukechronicle.com/articles/2012/07/02/admissions-yield-drops-two-points)) This is somewhat offset by the fact that ED yield is not necessarily 100%, because a few people decline for various reasons (usually financial). But let’s just assume 100% for the sake of simplicity.</p>
<p>Early Decision yield: 100%
Regular Decision yield: ~30%
Overall yield: 42%</p>
<p>Penn</p>
<p>Penn accepted 1148 early for a class of 2420 – meaning they filled 47% of the class early. (Source: [The</a> Daily Pennsylvanian :: Early decision admit rate drops slightly](<a href=“http://www.thedp.com/article/2011/12/early_decision_admit_rate_drops_slightly]The”>Early decision admit rate drops slightly | The Daily Pennsylvanian)) They accepted 2654 regular – which I calculated myself, as Penn did not explicitly state the number, so this might be slightly off. (Source: [The</a> Daily Pennsylvanian :: Admit rate holds steady at 12.3 percent](<a href=“http://www.thedp.com/index.php/article/2012/03/admit_rate_holds_steady_at_12.3_percent]The”>Admit rate holds steady at 12.3 percent | The Daily Pennsylvanian))</p>
<p>That means they expected 1272 of the 2654 regular admits to join the class. That’s a 48% yield for regular applicants.</p>
<p>Early Decision yield: 100%
Regular Decision yield: 48%
Overall yield: 63.3%</p>
<p>P.S. These calculations were done relatively quickly and I’m sure I made some errors – please correct if I did!</p>
<p>So, the overall yield is not simply an average of the ED and RD yields. Also, you’ll see that Penn accepted significantly more ED than Duke did (they are an Ivy, so I guess they have to keep up the appearance of selectivity ;)) so different schools accept different amounts of students early. Even Penn’s extensive use of ED falls short of 50%.</p>