"The fact that the rankings change each year is proof that this isn't an accurate measurement," says Justin Harman, director of communications at Princeton. Princeton dropped from a first-place tie with Harvard last year into a fourth-place tie with Yale this year.

For example, Caltech's jump from number four to number one can largely be attributed to change in the way school spending per student was evaluated. Rather than using a numerical ranking for a school's per capita expenditure, the survey now considers the actual dollar amount spent by the school on each student.

Caltech, with its wealth of lab facilities and a 3:1 student-to-faculty ratio, spends more than double what Harvard, Princeton and Yale spend on each student.

"Nothing changed at Caltech from last year to this year," says Caltech Vice Provost David L. Goodstein. "Things just changed at U.S. News."

Koonin says he agrees with Goodstein, and that he expects the rankings to change again next year.

"Institutions change on a much longer time scale than the news cycle," he said. "It's clear they changed the weightings and could change them again next year."

While U.S. News & World Report's issue may receive the most fanfare, other ranking systems come out each year as well. Kiplinger's and Money magazine each release annual lists of the best values among American colleges.