In January the Journal of Business and Finance Librarianship published a comparison of the six major MBA rankings and a review of the literature about them entitled “Comparing the Rankings of MBA Curricula: Do Methodologies Matter?” Included in this analysis are the rankings of Business Week, Economist Intelligence Unit, Financial Times, Forbes, US News & World Report, and the Wall Street Journal.
The most interesting part of the paper are the brief descriptions of each system’s methodology.

Although other business school ratings often make comparisons based on salary offers received by recent graduates, Forbes is the only source to take account of salaries before enrollment and to calculate a cumulative gain from the MBA over the first five years after graduation.

After a statistical analysis of the rankings over time, the authors see that “the ranking of U.S. MBA programs does not change greatly, at least over a 4-year period.”
Find the entire paper here.