No, One Limited Study Does Not Prove School Vouchers Don’t Work

You might be hearing a lot about the new study by Robert Pianta and Arya Ansari, “Does Attendance in Private Schools Predict Student Outcomes at Age 15? Evidence from a Longitudinal Study.”  Recently, opponents of private school choice have touted the study, claiming that it proves that vouchers do not improve student achievement.  In fact, the press release issued by my alma mater, the University of Virginia’s Curry School of Education, says,

Despite the arguments in favor of the use of vouchers or other mechanisms to support enrollment in private schools, ostensibly as a way to help for vulnerable children and families access a quality education, this study finds no evidence that private schools, exclusive of family background or income, are more effective for promoting student success,” said Robert C. Pianta, dean of the Curry School of Education and co-author of the study.

This study contradicts the rationale behind U.S. Education Secretary Betsy DeVos’ efforts to promote greater access to private schools, primarily through the administration’s earmark of more than $1 billion in the federal budget for private school vouchers and other school choice plans.

But Patrick Wolf, professor in the department of education reform at the University of Arkansas, says “not so fast.”

So, has this new study, forthcoming in the prestigious journal Educational Researcher, proven that private-school vouchers harm children? Hardly. It isn’t even a study of school vouchers. It isn’t designed to determine what caused the student outcomes it examines. Its findings are inconclusive, not negative. And, finally, it doesn’t have a large enough sample to prove much of anything.

Their lack of significant findings was obtained from an outdated, non-experimental, underpowered, sample-of-convenience analysis of places and people that were not participating in actual private-school voucher programs. They add the requisite, “findings should be interpreted with caution.” Readers would be wise to follow the sage advice that the authors themselves ignored.

Well said, Dr. Wolf.