Andrew J. Coulson & Jason Bedrick:

Should private schools be primarily accountable to parents or to government bureaucrats?
That’s the central question the Thomas B. Fordham Institute seeks to answer in the report it released Tuesday. The institute proposes that state governments should require private schools to administer state tests to all students participating in school-choice programs, and that the results should be publicized. Any private school the state deemed “persistently underperforming” would be expelled from the choice program.
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The Fordham Institute’s recommendation for regulating subsidized private schools is dangerous.”
This policy is well-intentioned, but a bad idea. It isn’t supported by the evidence and would be detrimental to the hundreds of thousands of students participating in school-choice programs nationwide.
First, the evidence: It is telling that the Fordham Institute cites only one study that suggests its policy “may boost student achievement.” Problematically, one of the authors of that study has already publicly cautioned against drawing this conclusion, noting that his finding is “enticing and suggestive but hardly conclusive.”
But even if the support of that one study were not in question, it would still only be one study. And a single study, no matter how carefully executed, is not a scientific basis for policy.

Much more on the “Common Core”, here.