When I was growing up in New York City in the 1990s, the public high schools had a very bad reputation. There were, however, exceptions, namely the three “exclusive” high schools that you could only get into by getting a high score on standardized tests — Stuyvesant, Bronx Science, and Brooklyn Tech. One interesting thing about these schools is that not only are they free for the students, they’re wildly cheaper in terms of per student spending than the fancy private schools in the city and the kids seem to do just fine in the college admissions sweepstakes. But of course the whole point of these schools is that they have higher quality inputs — better students — than your average NYC public school. So the mere fact that the graduates do better than the graduates of the average NYC public high school doesn’t tell us much about the learning that happens there.
Jay Matthews flags a fascinating study by Atila Abdulkadiroglu, Joshua D. Angrist, and Parag A. Pathak of Duke and MIT who look at exam schools in New York and Boston and conclude that there’s no there there. For both cities, it’s possible to look at the marginal cases — the kids who just barely made the grade or just barely missed out — and see if the small difference in ability that led to attending different high schools led to different outcomes. The answer is, in general, no: “Our estimates show little effect of exam school offers on most students’ achievement in most grades.” It’s neither the case that the teachers at the exam schools are systematically better than the ones at the regular schools, nor is it the case that the exam school offer any hugely important peer effects that bolster learning. The main exception is that “a Boston exam school education seems to have a modest effect on high school English scores for minority applicants.”
Consider it your daily reminder that when it comes to education, good outcomes are not the same as great teaching. The most reliable way to amass impressive alumni is to screen for impressive freshman. But at the policy level it’s more important to identify institutions that are unusually good at helping people learn, not institutions that are unusually good at screening.
UPDATE: Further commentary from Stuyvesant alum Reihan Salam is worth your time.