<p>Byerly, all that shows is that Harvard Yale and Princeton all feed very well to professional schools. Princeton is doing pretty well, seeing as it has no professional schools of its own and thus cannot give its undergraduates an advantage, as Harvard can an does.</p>
<p>There are more Harvard College grads at Harvard Law than grads of any other school; likewise there are more Yale College grads at Yale law.</p>
<p>Another thing that helps Harvard in this ranking is the size of its graduate schools, which allows Harvard grad schools to accept even more Harvard College graduates, giving them even more of a home turf advantage and thus a boost in these rankings.</p>