A string of high quality studies is finding that students benefit academically from attending a charter school rather than a traditional public school.
First we had a random-assignment study of Chicago charter schools by Caroline Hoxby and Jonah Rockoff that found “that students in charter schools outperformed a comparable group of lotteried-out students who remained in regular Chicago public schools by 5 to 6 percentile points in math and about 5 percentile points in reading.”
Then Hoxby conducted a random-assignment study of charter schools in New York City and found: “that the average effect of the charter schools on math is 0.09 standard deviations for every year that a student spends in his or her charter school. The average effect on reading is 0.04 standard deviations for every year that a student spends in his or her charter school.”
Then Kevin Booker (Mathematica), Tim Sass (Florida State), Brian Gill (Mathematica), and Ron Zimmer (Rand)used a well-designed instrumental variable analysis to see whether charter middle-schoolers who continue to charter high schools are more likely to graduate. They are.
And most recently a random-assignment analysis of charter schools in Massachusetts led by Tom Kane at Harvard and Josh Angrist at MIT found that charter school students accepted by lotteries significantly outperformed their counterparts in traditional public schools, unless the charter school was operated by the teacher unions.
In light of these high quality studies, it is harder to oppose charter schools on a scholarly basis. And with the clear support of charters from the incoming Obama administration, it is getting harder to opposed charter schools on a political basis — at least at the national level.
But don’t expect to see the teacher unions waving a white flag despite their losses in research and national politics. They don’t need facts or the support of the US Department of Education so long as they continue to dominate local school politics.
And that is exactly why they have focused on organizing local charter schools to neutralize the threat to their grip on local school politics. As my colleague Marcus Winters writes today in the New York Post, the unions managed to organize two successful charter schools in New York City. The fact that union-run charter schools in Massachusetts trailed the non-union charters in performance is not of concern to the unions. It isn’t about student achievement; it’s about keeping their hold on power even as the facts pile up against them.
Posted by Jay P. Greene 
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