Purpose/Objectives: Existing research has investigated the effects of using individual incentives and positive reinforcements to influence children to eat more fruits and vegetables for lunch and snack during school. This study explored using group-level incentives to motivate children in a Wisconsin elementary school to eat more fruits and…

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.…