Little is known about the skills children need to successfully collaborate with classmates on academic assignments. The purposes of this study were to identify grade-schoolers' collaborative skills, evaluate the importance of identified skills for collaborative work, and determine whether differences in skill use were related to children's social…

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.…