According to a recent study, teacher performance based pay based on the progress of entire schools, not the progress of individual students, lead teachers to exert more effort and raise student achievement.  Professors Thomas Ahn of the University of Kentucky and Jacob Viglor of Duke found that North Carolina’s teacher incentive program, which rewards teachers based on school-wide performance, found that school wide performance incentives have a stronger effect on increasing teacher time in the classroom and improving student standardized test scores than individual teacher incentives.  The study also concludes that school-wide incentives also are four times more cost effective than education reforms such as reducing class size. However, the results of this study do differ from other studies on the effects of performance-based pay for teachers, on student performance and teacher effort.  However, with increasing emphasis on accountability for academic improvement at both the federal and state level, the debate appears to have shifted from whether or not teachers should be paid for performance to how they should be should be paid for performance.  Therefore, more research should be expected in the area of incentive-based pay in education.  A key to evaluating these and upcoming studies will be examining the differences in methodology in conducting the studies.  More rigor should be emphasized in both the evaluators designing these studies and the policymakers and stakeholders critiquing them.