Thanks very much everyone!
I had another question about the application process. For clinical PhDs each person applies to one mentor (for the most part), but ranks several others (usually). For a clinical personal statement, I would tailor it just to that one top person, because that usually works best (from what I understand, if you don't rank a certain faculty member first, they don't even look at you).
I know that at some IO programs this is not the case and thus one writes a more general personal statement (e.g. Minnesota). But I was wondering, is it still encouraged to be specifically interested solely in one professor, is there any advantage to that? Or does it work better, for those programs (like Columbia, which is Social Organizational, though not technically IO is similar) that don't have you apply to a mentor, to express interest in as many of the faculty that you are actually interested in?