Do private schools do a better job of educating our kids than public schools? Lots of people think so. But a new, large-scale statistical analysis of the 2003 NAEP test results suggests that when you control for things like income, race, home environment, and so forth, the performance of private schools actually turns out to be worse or about the same as that of public schools, not better.
From the NY Times story, Public-School Students Score Well in Math in Large-Scale Government Study,
A large-scale government-financed study has concluded that when it comes to math, students in regular public schools do as well as or significantly better than comparable students in private schools.
The study, by Christopher Lubienski and Sarah Theule Lubienski, of the University of Illinois at Champaign-Urbana, compared fourth- and eighth-grade math scores of more than 340,000 students in 13,000 regular public, charter and private schools on the 2003 National Assessment of Educational Progress. The 2003 test was given to 10 times more students than any previous test, giving researchers a trove of new data.
Though private school students have long scored higher on the national assessment, commonly referred to as “the nation’s report card,” the new study used advanced statistical techniques to adjust for the effects of income, school and home circumstances. The researchers said they compared math scores, not reading ones, because math was considered a clearer measure of a school’s overall effectiveness.
The study found that while the raw scores of fourth graders in Roman Catholic schools, for example, were 14.3 points higher than those in public schools, when adjustments were made for student backgrounds, those in Catholic schools scored 3.4 points lower than those in public schools. A spokeswoman for the National Catholic Education Association did not respond to requests for comment.
… The study also found that charter schools, privately operated and publicly financed, did significantly worse than public schools in the fourth grade, once student populations were taken into account. In the eighth grade, it found, students in charters did slightly better than those in public schools, though the sample size was small and the difference was not statistically significant.
“Over all,” it said, “demographic differences between students in public and private schools more than account for the relatively high raw scores of private schools. Indeed, after controlling for these differences, the presumably advantageous private school effect disappears, and even reverses in most cases.”