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.…

This report focuses on the extent to which students who are academically far off track in fourth or eighth grade in Kentucky catch up by eighth or eleventh grade. We studied three recent cohorts of Kentucky students whose eighth-grade ACT Explore® scores were more than one standard deviation below the ACT Explore benchmark scores associated with…