<p>I think the regional preference may be a factor especially when you are talking about LACs or smaller universities => graduate programs. For instance, a student at Haverford is more likely to get respect in the Northeast than in the Northwest, just as a Pomona student will be respected more in the West than in the East or South. That doesn’t mean that students from those LACs can’t get into graduate school outside of their regions, only that people who live in those regions (i.e. faculty members) are more likely to be familiar with the rigors of the undergraduate education. </p>
<p>The faculty members on admissions committees don’t work in admissions full-time the way undergraduate admissions people do, so they are more likely to be influenced by their own academic/research sphere, which may, or may not, be regional. When you are talking about a lot of applications for few spots, you get into the realm of splitting hairs as the pool of qualified applicants gets winnowed down. Faculty bias (evaluation of undergraduate institution, research area, who wrote the LORs – even department politics) can come into play as they select the final group. If the adcom respects a particular university, then they will be more likely to accept an applicant from that university over one with a similar profile who attended a university with which they are less familiar.</p>