Two new studies of private school voucher programs – one in Indiana and the other in Louisiana – confirm that students using vouchers to attend private schools will see a drop in their academic achievement.

In both programs, students who use a voucher experience a decrease in math test scores in the first few years. This is in line with other recent studies we’ve seen of programs in Ohio and the District of Columbia, where students using vouchers are doing even worse academically.

Voucher proponents argue that these two new studies show these students might rebound and catch back up with their peers academically. But the studies don’t quite support this conclusion. In addition, the argument that voucher students will certainly experience a decline in academic achievement but if they wait it out for four years, they might see improvements is not a very compelling one. Four years is a long time in a child’s education; it’s much too long to gamble on the loss of critical foundational learning for students who need it the most.

Two new studies cast doubt on the effectiveness of vouchers.

Here are some of the details from the studies:

Indiana: Students using a voucher to attend a private school see declining test scores in math. The negative effect on students’ math scores is worse in the first two years. By year four, however, students generally end up with math scores on par with their peers. The study also notes that the sample of students is so small after year four that it’s difficult to accurately measure whether the students truly catch back up. Overall, students using a voucher see no improvement in test scores in English Language Arts (ELA) compared with their peers in public school. But special education voucher students do experience a loss in ELA scores.

Louisiana: A previous study of the program found that students using a voucher had negative results in math test scores in the first two years, compared to students who did not use a voucher. Voucher students also lost points in ELA scores in the first year, with uncertain results in the second year.

The new study found that in year three, voucher students had slight gains in ELA scores and slight losses in math scores compared to students not using a voucher, but that neither were statistically significant. The uncertainty is in part because by year three, there was a declining statistical power due to fewer students remaining in the program.

When the student numbers were broken down further, however, the results showed a greater loss in math scores for the youngest students – those applying to earlier elementary grades.

Both studies noted that their sample sizes had become smaller after years three and four at least in part because many students chose to return to public school. And that makes sense: If the program isn't working for even just one or two years, why would you remain in it?

And perhaps an even more important question: In the face of mounting evidence demonstrating negative results in academic achievement, how can lawmakers continue to push for such proposals?

President Donald Trump and Secretary of Education Betsy DeVos continue to advocate for new federal voucher programs. It may become harder to ignore the evidence that voucher programs don’t work, as it keeps mounting around them. At AU, we will continue to highlight the failings of private school voucher programs. After all, our tax dollars should support the public school system, which educates 90 percent of our students, rather than diverting it to private religious schools.

For more about the many flaws in private school voucher programs, check out the resources of the National Coalition for Public Education, which AU co-chairs.