Thursday, October 09, 2008

Science News Rating The Rankings

The single best school in the country is Penn State. Then again, maybe it’s Princeton. Or perhaps Johns Hopkins, or Harvard, or Notre Dame …

Each of these schools could legitimately claim to be on top, according to a mathematical analysis, posted recently on, of the data U.S. News & World Report uses to generate its influential and controversial rankings of American undergraduate institutions. It all depends, the researchers say, on what your priorities are.

The magazine uses seven key factors in its ratings, including things like percentage of alumni who donate, acceptance rates for admission, and spending per student. Lior Pachter of the University of California, Berkeley and Peter Huggins of Carnegie Mellon University reasoned that all these factors are probably relevant to the quality of a university, but one student might value a university with a low student-faculty ratio, for example, while another might care more about research funding. Was there a way to analyze the data, they wondered, that wouldn’t rely on an arbitrary selection of priorities?

Techniques they’d developed for a completely different problem — aligning gene sequences to understand evolutionary changes — could be adapted to do just that, they realized. Biologists commonly analyze the differences between the DNA of two closely related creatures in order to understand how they evolved. To do that, researchers first have to decide how to line the two gene sequences up, identifying the segments that are identical and the places where DNA has have mutated or moved around or been deleted. But this alignment requires some guesswork: How likely, for example, it is that a gene will have mutated, and how likely is it that it simply will have been deleted? Biologists have little basis for deciding that, Pachter says, just as U.S. News has little basis for deciding how important one of its factors is for a particular person.

Science News / Rating The Rankings
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