Martin Carnoy is a professor at Stanford University who has studied education systems around the world.

Carnoy wrote a report for the Economic Policy Institute about the efficacy of vouchers, or their lack thereof. The report is titled “School Vouchers Are Not a Proven Strategy for Improving Student Achievement.” Carnoy reviews the longest-running voucher programs in the U.S. and other countries and finds little evidence that they improve student achievement.

Here is his summary:

“This report seeks to inform that debate by summarizing the evidence base on vouchers. Studies of voucher programs in several U.S. cities, the states of Florida, Indiana, Louisiana, and in Chile and India, find limited improvements at best in student achievement and school district performance from even large-scale programs. In the few cases in which test scores increased, other factors, namely increased public accountability, not private school competition, seem to be more likely drivers. And high…