<p>I don’t know anything about the statistics, but I did not go to an Ivy for undergrad but am currently at an Ivy for grad school. I would roughly estimate that about half of the grad students in my program attended Ivies–a little less than half of next year’s incoming class did–with Harvard being the most well-represented, and the other half attended a broad range of liberal arts colleges, state universities, relatively prestigious private universities (Johns Hopkins, Chicago, Stanford, etc.), and foreign universities, especially Oxbridge. </p>
<p>Like I said, that’s only from personal experience–I have no hard data to back that up. Also, I’m in a humanities department, and can’t really say whether programs in the sciences or social sciences have a similar breakdown.</p>