WHICH IS WHY YOU HAVE TO IMPOSE STANDARDS:

Last week, the Education Department, which she runs, released a careful study of the District of Columbia's use of school vouchers, which she supports. The results were not good.

Students using vouchers to attend a private school did worse on math and reading than similar students in public school, the study found. It comes after other studies, in Ohio and elsewhere, have also shown weak results for vouchers. [...]

Unlike most voucher programs, many charter-school systems are subject to rigorous evaluation and oversight. Local officials decide which charters can open and expand. Officials don't get every decision right, but they are able to evaluate schools based on student progress and surveys of teachers and families.

As a result, many charters have flourished, especially in places where traditional schools have struggled. This evidence comes from top academic researchers, studying a variety of places, including Washington, Boston, Denver, New Orleans, New York, Florida and Texas. The anecdotes about failed charters are real, but they're not the norm.

Douglas Harris, a Tulane professor, says the difference between charters and vouchers boils down to "managed competition" versus the "free market." Susan Dynarski of the University of Michigan talks about charters' successfully combining flexibility and accountability. Joshua Angrist of M.I.T. says, "Flexibility alone is not enough."

Crucially, many charters are open to all comers, which means their success doesn't stem from skimming off the best. And the schools' benefits extend beyond test scores to more meaningful metrics, like college graduation.

The District of Columbia study highlights the charter/voucher contrast in a neat way. The voucher results look so weak -- even worse than elsewhere -- partly because the city's charters are so strong. That is, voucher recipients are being compared with children at higher-performing public schools than in the past, and the voucher schools aren't keeping up.

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