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…

Based on cognitive load theory, the effect of different levels of instructional detail and expertise in a simulation-based environment on learning about concepts of correlation was investigated. Separate versions of the learning environment were designed for the four experimental conditions which differed only with regard to the levels of written…

We examined selected situational emotions (interest, well-being and anxiety) experienced by 291 secondary school tenth graders during a hands-on gene technology lesson. Two different instruction groups (I-1, I-2) participated in the same teaching unit, in which four basic gene technology experiments were performed. Using a modified…

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.…