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.…

The purpose of this study was to investigate the effectiveness of the CompassLearning Odyssey® Math (Compass Math) program on increasing mathematics achievement scores for students in an urban environment over two consecutive years. Thousands of schools and districts across the country currently utilize the Compass Math program for their students…