Education policymakers have shown increased interest in incentive programs for teachers based on the outcomes of their students. This article examines a program in which bonuses were awarded to teams of middle school teachers based on their collective contribution to student test score gains. The study employs a randomized controlled trial to…

Background: Cluster-randomized experiments that assign intact groups such as schools or school districts to treatment conditions are increasingly common in educational research. Such experiments are inherently multilevel designs whose sensitivity (statistical power and precision of estimates) depends on the variance decomposition across levels.…