<p>@southernHope, here is the unspoken theory.</p>
<p>There are more hooked poeple living near said colleges. Not just alumni kids. Imagine faculty/staff’s kids. As a benefit, they are likely to be taken if “qualified”. Now those may rank 10th, 20th or 30th within their schools. It will be bad publicity for top colleges to routinely take those, but skip the higher ranked kids in the same high schools. So the colleges will take a few kids ranked higher than the hooked ones to pacify their neighbors.</p>
<p>Now once they do that to one or couple of schools, they can’t treat another high school next door same way as one that’s thousand of miles away. So they will take quite a few from those too. So you will see a diffusion effect with the highest concentration around the college. This happens to all top private colleges.</p>
<p>Also taking local kids produces higher yield since they are likely to attend, especially for those unlikely to be accepted at other schools across the country.</p>
<p>Hope this explains.</p>