Objectives: We examined the longitudinal relationship between cardiovascular fitness (CRF) and academic performance (AP) among students in a diverse public school district. Furthermore, we determined whether the relationship between CRF and AP varied by student sociodemographic characteristics. Methods: This study used data from 2005-2006 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.…

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.…