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.…

"Identifying Success in Schools and Programs for English Language Learners in Boston Public Schools," of which this report is one part, is a project commissioned by the Boston Public Schools as part of this process of change set in motion by the intervention of the state and the federal governments on behalf of Boston's English language…