Atlantic Monthly: Going Public

From the May Atlantic Monthly column Primary Sources (subcription required) comes some interesting news:

Going Public

Students at private schools tend to outscore their public- school counterparts on standardized tests—but are private schools really better at educating their students, or do they just enroll more pupils from socioeconomic backgrounds that foster academic achievement? A new study takes up this question by examining math scores from the 2000 National Assessment of Educational Progress, which tested more than 28,000 fourth and eighth graders nationwide. As expected, private-school students earned substantially higher math scores on the NAEP tests than did students in public schools—but when the authors controlled for socioeconomic status, the private-school advantage completely disappeared. Indeed, when the authors compared students within socioeconomic brackets, rather than across them, the students from public schools actually outscored their private-school peers, in the fourth and eighth grades alike.

—“A New Look at Public and Private Schools: Student Background and Mathematics Achievement,” Sarah Theule Lubienski and Christopher Lubienski, Phi Delta Kappan

What does it mean? I'm not sure. But it fits with what I observe about public and private school kids.