<p>^Well, for one, because it provides an advantage to the applicants – people who get in can potentially apply to fewer schools during the RD round, and people who are deferred have the opportunity to send in additional materials to support their cases.</p>
<p>From the perspective of the admissions office, it’s also useful to spread out the applications somewhat. It’s really logistically challenging for them to evaluate all the applications they do during the RD round in the time allotted, so it’s good to have some percentage of the applicant pool apply EA.</p>