I discuss the topic (and include a downloadable paper) at the new law school site.  Some of the issues are specific to the legal academy, but the topic may nonetheless interest those in other fields.

UPDATE:  There are two special challenges that one faces in the evaluation of law schools, in contrast to philosophy departments.  First, whereas faculty quality is clearly paramount in the latter instance, it is not necessarily so in the former case.  Second, law, unlike philosophy, is not a coherent intellectual discipline, so that reputational results are less cohesive and more sensitive to sub-field.