The Institute for Education Sciences at the U.S. Department of Education released a study last week showing that students randomly selected to receive a voucher under the D.C. Opportunity Scholarship Program had lower math achievement after one year compared to students who were not selected. These are discouraging results for school choice advocates, for Republicans in Congress who are trying to reauthorize the federally-funded program, for school choice supporter and Secretary of Education Betsy DeVos, and for the DCOSP program specifically.

These results are clear evidence that, at least on some measures, the program not only failed to boost students’ performance, but actually made it worse. By comparing students who won a scholarship through a random lottery to those who did not, the study establishes that the differences between them were actually caused by the program.