This paper examines the roles of multimodality and thematic patterns in the teaching of the particle model of matter. Although the particle model is a fundamental topic in science education, there is no consensus on (1) whether or not the model should be introduced in early grades and (2) how to introduce the model to students for the very first…

When evaluators plan site-randomized experiments, they must conduct the appropriate statistical power analyses. These analyses are most likely to be valid when they are based on data from the jurisdictions in which the studies are to be conducted. In this method note, we provide software code, in the form of a SAS macro, for producing statistical…

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.…