"One common statistic used to evaluate colleges, for example, is called “graduation rate performance,” which compares a school’s actual graduation rate with its predicted graduation rate given the socioeconomic status and the test scores of its incoming freshman class.... Tulane, given the qualifications of the students that it admits, ought to have a graduation rate of eighty-seven per cent; its actual 2009 graduation rate was seventy-three per cent. That shortfall suggests that something is amiss at Tulane."
Anyone else think that those numbers for the 2009 graduating class has anything to do with the fact that Hurricane Katrina hit during the first few weeks of '09's freshman year, forcing students at Tulane (which is located in New Orleans) to take leaves of absences or transfers?
Just goes to show, in addition to inherent biases, rankings also don't capture extenuating circumstances that can have drastic short term effects that go unnoticed.