Public vs. Private

PUBLIC vs. PRIVATE….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.

The study analyzed only the math portion of the NAEP test, and the results from the 4th grade test are shown below. The red line shows the average public school score, and as you can see from the black bars on the graph, the raw scores for most types of private schools are higher than the public school average. However, much of this difference is due to the fact that private schools attract better kids in the first place, not because the schools themselves are better.

So what would happen if both types of schools had similar student bodies? Those results are shown for private schools in the gray bars in the graph, where test scores are controlled for demographics, and they’re considerably lower than the public school average. In other words, if you took two similar kids and sent one to a public school and one to a private school, the kid in the private school would probably do a little worse than his public school twin. (Note that a difference of 10 points is roughly equal to one grade level.)

The 8th grade results are better, with most private schools scoring about the same as public schools. The only exception is the conservative Christian schools, which continue to score considerably lower than public schools ? although the sample size is small enough that the results aren’t conclusive.

I don’t imagine that one study will change any minds, but the size and sophistication of this one should at least give us pause. The full report is here. The New York Times summarizes the results here.