A Stanford researcher looked at a quarter-century of evidence and concluded that school vouchers have no track record to show they significantly boost test scores—although there is plenty to suggest that voucher schemes work against struggling students and are disincentives for educators because they erode features like pensions and due process protections.
The Economic Policy Institute published the new report, which was authored by Stanford Graduate School of Education professor Martin Carnoy and initiated shortly after the nomination of Betsy DeVos as education secretary. DeVos is a lifelong advocate of vouchers, and the report was an investigation into what hard benefits could be found in vouchers; Carnoy examined a wide range of programs, including ones in Indiana and Louisiana as well as Milwaukee and, Washington, D.C. Milwaukee, the nation's longest-standing voucher program, "offers no solid evidence of student gains in either private or public schools," the report concludes.
If you're looking for signs that vouchers yield significant learning gains, "the evidence is very weak," Carnoy told reporters. "They also carry hidden costs, and they're distracting us from other solutions that could yield much higher returns."