Earlier I wrote about this CREDO report on the effectiveness of charter schools in Michigan, with the headline, "Charter Schools More Effective." Today my MEA e-newsletter sent me this gem from the Great Lakes Center for Education Research, which links to a review of the study by somebody else. (I believe this is why people refer to the self-sustaining nature of bureaucracy.) That person, one Andrew Maul of U Colorado Boulder, writing for the Think Twice Project (not a project I'm familiar with), suggests that there is almost no difference in performance between charter school students and public education students. The effect of charter schools was responsible for a performance improvement of .1%, considerably less than the effect of having a teacher that knows how to use compare-and-contrast charts effectively.
Caveat lector: I still have not read the original CREDO study, nor have I read the full Maul report. I pass this along as a summary of news, not as a position. However, clearly this new summary of other people's research matches more neatly with my biases than the summary of the original report.