Don't pay attention to the primary care rankings. They are completely subjective and don't really tell you anything useful about the school. They are tallied based on what other deans think of other schools. Therefore, if the dean at school X has a buddy who is the dean at school Y, he will get a high mark. There are no numbers to really back up anything. Research rankings are based on funding, average MCATs and GPAs, big faculty names, etc. At least this is what the doctors I am shadowing this summer have told me (they are all MDs, FACPs, and one is a Northwestern professor).