NEWSWEEK recently published its ranking of the nation's "100 Best" public high schools. Unlike, say, U.S. News & World Report's rankings of law schools, which can be read as a kind of Michelin Guide for aspiring lawyers, the Newsweek list offers no such concrete consumer service. It may feed the vanity of those already attending one of the top schools ("See if your high school made Newsweek's cut," the magazine advertises). But only about a third of American high school students choose to attend a high school other than their local one. And in any case, the relevant batch from which most parents pick is local, not national.

But what's really unique about Newsweek's list is that it's based on only one criterion: the proportion of students who, in a given high school, take--not pass, just show up for--any Advanced Placement or International Baccalaureate test.

For a critic of this approach, one need look no further than the College Board itself, which designs and markets Advanced Placement courses and exams. On its website, it says that AP exams "should never be used as a sole measure for gauging educational excellence and equity," and calls media rankings that do so "problematic." Education experts are just as critical. Chester E. Finn Jr. of the Thomas B. Fordham Foundation compares Newsweek's system to judging people's health only by taking their temperature. "You'd be overlooking their blood pressure" and every other indicator of physical well-being, says Finn. Tom Loveless of the Brookings Institution is even more adamant: "Any ranking system worth anything at all must have at its core student learning. And this one does not."

How could Newsweek rank high schools by only a single criterion, one that doesn't even measure whether students are learning anything? Two words: Jay Mathews. He is the author of the Newsweek list as well as a staff writer for the Washington Post and one of the top education reporters in the country. His enthusiasm for Advanced Placement courses might be described as monomaniacal.

In 1955, the College Board introduced Advanced Placement courses, assuming control of a small experiment in which Ivy League professors and teachers from some of the tonier prep schools had hoped to make high schools and colleges work as "two halves of a common enterprise." Academically rigorous, heavy on homework and reading, and culminating in exams that many universities will give credits for, AP courses are deservedly hailed as a great equalizer. The poster children are no longer from Andover, but from places like Garfield High School in East Los Angeles, where Jaime Escalante (the math teacher portrayed in Stand and Deliver) taught low-income immigrant students to pass the College Board's fearsome calculus exam.

Mathews, then the Los Angeles bureau chief of the Washington Post, was the first reporter to delve into the pedagogical story of how Escalante confounded the low expectations of a condescending school system by inspiring minorities to prove themselves in the same courses and exams that rich kids from rich schools took. The idea caught fire--and it continues to burn. According to the College Board's most recent report, the number of African-American students who have passed an AP exam has more than doubled since 1996 and the number of Latinos with a passing grade has almost tripled. Education secretary Margaret Spellings called this "further proof that our children respond when we challenge them academically."