I'm interested in this too. From what I gather, ranking is a pretty subjective term especially when you view it from income class or from quality of dentists the school graduates. You can say a schools ranking is by gpa/dat of incoming students, number of applicants, gpa of graduating SRs, or test scores of national boards. I applied to a school last year that claimed to be the number one dental school in ranking of the national boards I believe but I never found any such ranking to validate their claim. I'd love to see where the schools I'm applying for this time are ranked.