There's so much back and forth about teachers--about what makes a good one, about how to attract good ones and deal with the bad ones, about the unions and the ed schools. Teach for America offers an intriguing spin on it all.

Get this: This year, 25,000 college seniors applied to do Teach for America. 3,700 were accepted. Among them were 11% of Yale's graduating class, 9% of Harvard's, and 10% of Georgetown's. That's pretty humanitarian, considering the pay, and also pretty savvy. As the Wall Street Journal points out, Teach for America is a great way to sidestep the expensive, time-consuming, politicized, and altogether annoying ed schools. It's also, it turns out, a great way to improve the caliber of instruction.

The American Federation of Teachers commonly derides Teach for America as a "band-aid." One of its arguments is that the program only lasts two years, barely enough time, they say, to get a handle on managing a classroom. However, it turns out that two-thirds of its grads stay in the education field, sometimes as teachers, but also as principals or policy makers.

More importantly, it doesn't matter that they are only in the classroom a short time, at least according to a recent Urban Institute study. Here's the gist: "On average, high school students taught by TFA corps members performed significantly better on state-required end-of-course exams, especially in math and science, than peers taught by far more experienced instructors. The TFA teachers' effect on student achievement in core classroom subjects was nearly three times the effect of teachers with three or more years of experience."

Jane Hannaway, one of the study's co-authors, says Teach for America participants may be more motivated than their traditional teacher peers. Second, they may receive better support during their experience. But, above all, Teach for America volunteers tend to have much better academic qualifications. They come from more competitive schools and they know more about the subjects they teach. Ms. Hannaway notes, "Students are better off being exposed to teachers with a high level of skill."

The strong performance in math and science seems to confirm that the more specialized the knowledge, the more important it is that teachers be well versed in it. (Imagine that.) No amount of time in front of a classroom will make you understand advanced algebra better.

Teach for America was pleased, but not exactly shocked, by these results. "We have always been a data-driven organization," says spokesman Amy Rabinowitz. "We have a selection model we've refined over the years." The organization figures out which teachers have been most successful in improving student performance and then seeks applicants with similar qualities. "It's mostly a record of high academic achievement and leadership in extracurricular activities."