Study: Indiana voucher students fall behind in math

Students who use Indiana’s voucher program to transfer from public to private schools aren’t seeing the test-score gains they may have expected. When it comes to academics, they could be better off staying in their local public schools, according to a long-awaited study released today.

The study, by Joe Waddington of the University of Kentucky and Mark Berends of the University of Notre Dame, finds that voucher students experience significant losses in mathematics achievement after they transfer to private schools. Receiving a voucher did not have a significant effect on English/language arts test performance.

The findings are based on a detailed and rigorous analysis of ISTEP-Plus scores for students who received private school vouchers in the first four years of Indiana’s program.

The study follows a spate of negative evaluations of voucher programs in Ohio, Louisiana and Washington, D.C. But Indiana’s program is especially helpful to study. It’s the nation’s largest and most generous voucher program, enrolling more than 34,000 students; and it is unusual in that private schools that participate must administer state standardized tests the same as public schools.

You can read a detailed report on the study on the National Public Radio website.

Waddington and Berends analyzed test scores for voucher and non-voucher students in grades 3-to-8 from 2011-12 to 2014-15. They used sophisticated statistical techniques to ensure they were making apples-to-apples comparisons and multiple approaches to add confidence to their findings.

The study looks only at voucher students whose family income was low enough to qualify for free or reduced-price school meals. Indiana also provides a “half voucher” to students from middle-income families; those students were not included in the study.

Voucher students, on average, experienced an annual loss of 0.10 standard deviation in math compared to peers who stayed in public schools. That’s not as big as the loss found in some voucher studies, but it’s significant. For comparison, it’s twice the impact of a 2015 study that was widely interpreted to show urban charter schools are superior to urban public schools.

The study suggests students who stick it out in private schools may eventually catch up. Losses in math were greatest in the first and second year after students moved to a private school but disappeared for voucher students who stayed for four years. Conversely, voucher students who transferred back to a public school had the worst outcomes. Researchers had four consecutive years of data for a limited number of students, however.

While the study found no overall effect from vouchers on English/language arts performance, voucher students attending Catholic schools made slight gains in English/language arts. Students saw losses in math performance in all types of private schools. Special-education students with vouchers saw larger learning losses while English language learners did not see losses or gains.

The study suggests possible explanations for the results. Curriculum in some private schools may not be aligned with state standards, especially in math. And some private schools may not have been prepared for low-income and relatively low-achieving students who received vouchers.

The authors acknowledge that test scores don’t tell us everything we need to know about schools, and they point out that parents may use vouchers to send their children to private schools for reasons other than academics. They also note the difficulty of studying the voucher program for the ever-growing number of Indiana students who receive vouchers without having ever attended a public school.

Berends and Waddington shared preliminary results from their Indiana voucher research at a conference in 2015, and the findings have been referenced in a Brookings Institution report and articles in the education media. Their paper is being revised for publication in an academic journal.