This report looks at student growth in Arkansas school districts disaggregated by district poverty and by the district's value-added performance relative to other districts. We estimated district value-added performance statistics by subject and grade level (8 and 11-12) for longitudinal student cohorts, using statistical models that adjusted for…

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.…