<p>Really?</p>
<p>Isn't it true that 40-50% of MIT's graduate enrollment is made up of the school's own undergrads?</p>
<p>I've never heard of the word "incest" being used in this context, by the way.</p>
<p>Like I said, it depends on the department. The MIT biology department, for example, greatly frowns on incest. For example, molliebatmit reports that the bio department just recently revoked that incest rule, and they still don't really bringing in their own undergrads. I believe the same is true for chemistry. </p>
<p>Caltech definitely has a rule against incest within certain departments. That's why my brother didn't stay at Caltech. I know he wanted to stay, but his department didn't want him to stay. </p>
<p>The point is, it's all department-specific. Some departments at some schools like incest. Others don't. </p>
<p>A major reason why you see so many of MIT's undergrads going to MIT grad school, but not as many Berkeley undergrads going to Berkeley grad school is that, quite frankly, MIT undergrads are more qualified than Berkeley undergrads, such that more MIT undergrads are qualified to get into MIT for grad school than there are Berkeley undergrads that are qualified to get into Berkeley grad school. In fact, the MIT undergrads are often times so good that many of them are, honestly, better than many MIT grad students.</p>