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I suspect that, at a school like Princeton, the ratio of non-senior (i.e., alumni) applicants and senior applicants is 50:50, and maybe even 55:45. One reason is that a higher percentage of Princetonian’s families are weathier and/or more knowledgeable in how to “do premed” than their counterpart (on average) at state universities. The student from such a family 1) may not be in a rush to build up their credential by the end of junior year – they may want to have additional “edges” in their application by choosing to have another year to beef up their ECs. 2) may want to do more “something else” (including having fun in their “eating clubs”) before they plunge into the medicine career.</p>
<p>I even heard a rumor that many from such a “high-calibered” school would choose to major in a non-science area they really excel at while in college (so they take fewer science classes than a typical science major premed to insure a higher BCPM GPA), and then attend a post-bacc program or take some other local less competitive university to finish up the remaining premed classes. (Read: their family can afford this expensive route.)</p>
<p>I even suspect that the medical school students as a group are more likely from families with a better access to (financial, academic, research, volunteering, clinical, or connection to people in careers indirectly or directly related to medicine, etc.) resources.</p>