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.…

Differentiated instruction is commonly believed to be critical to improving the quality and efficiency of teachers' instructional repertoires (Fischer & Rose, 2001; Tomlinson, 2004). Tomlinson (2000) describes differentiation in four domains: content, process, product, and learning environment. Content differentiation involves varying…

The authors conducted an experiment during the 2003-2004 school year to determine whether "On Our Way to English" ("OWE"), a product to help elementary students learn to read and speak English, was more effective in a California and a Texas school district than materials already in place. In the California study, 384 English…

The authors were asked to find out whether "On Our Way to English" ("OWE"), a supplementary, text-based product to help elementary school students learn to read and speak English was more effective in a California and a Texas school district than the materials the districts already had in place. They conducted an experiment…