Merit Pay Found to Have Little Effect on Achievement

Nearly 300 middle school mathematics teachers in Nashville, Tenn., voluntarily took part in the Project on Incentives in Teaching, a three-year randomized experiment conducted by researchers affiliated with the National Center on Performance Incentives at Vanderbilt University. It was designed to study the hypothesis that a large monetary incentive would cause teachers to seek ways to be more effective and boost student scores as a result.

But it yielded only two small positive findings, limited to 5th graders in the second and third year of the experiment. No effects were seen for students in grades 6-8 in...