The Indiana Choice Scholarship Program (CSP) study revealed a similar, but perhaps more encouraging trend. Students using the program performed on par in mathematics and even made gains in English language arts by the fourth year.
This upward trend is not unusual. The recent review of 19 experimental voucher studies around the world conducted by researchers at the University of Arkansas shows that private school choice programs need a few years to start improving test scores. This is likely because children need to adjust to their new educational settings and private institutions must respond to the environmental shift in the market for schooling.
The positive test score trend can be interpreted in two different ways. One is that private schools in voucher programs adjust and improve after a few years of participation. The other possibility is that incentive structure for private schools shifts from a focus on character education towards a focus on test scores, since most states use test scores as their preferred educational accountability measure.
So what does the scientific evidence have to say?
There have been 17 experiments, including the one in Louisiana, on the effects of private school choice on student achievement in the United States. Out of these studies, only two have shown negative impacts on student test scores, four have found no effects and eleven have found positive effects overall or for subgroups of students.
The scientific evidence on essential long‐term outcomes is more hopeful for private school choice programs. University of Arkansas’s Dr. Patrick J. Wolf led an experiment on the D.C. Opportunity Scholarship Program (OSP) which found that winning a random lottery to use a private school voucher increased students’ likelihood of graduation by 21 percentage points. The University of Wisconsin — Madison’s Dr. Joshua Cowen led a quasi‐experimental study on the Milwaukee Parental Choice Program, finding an increase in the likelihood of graduation by four percent.
Another experiment examined charitable giving and found that Ohio voucher students are more likely to donate. And the only quasi‐experimental study examining impacts on criminal activity, conducted by me and Patrick J. Wolf, found that Milwaukee voucher students are around half as likely to become criminals as adults than their traditional public school peers.
Although the “failure” of private school choice is continuously echoed by education reporters across the nation, the scientific evidence largely suggests otherwise.