Colleges and universities will be giving U.S. News & World Report lots of free publicity today as they boast about their advances in the magazine's annual college rankings. But in one key respect, colleges are becoming notably less helpful to the magazine. Presidents are less likely than in years past to fill out the evaluations that are a key part of the rankings methodology. This follows a few years of stability or slight gains in participation -- following some declines amid a push by some rankings critics for colleges to boycott the "peer evaluations."