The most rigorous experimental study of performance-based teacher compensation ever conducted in the United States shows that a nationally watched bonus-pay system had no overall impact on student achievement--results that are certain to set off a firestorm of debate. The study, known as POINT for the Project on Incentives in Teaching, was a three-year randomized experiment conducted by researchers affiliated with the National Center on Performance Incentives. 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 years of experiment. No effects were seen for students in grades 6-8 in any year of study. At the same time, however, participating teachers did not report finding the pay program's goals for students out of reach or its impact on school culture damaging, two concerns that have been among those voiced by opponents of performance pay.