Education experiments frequently assign students to treatment or control conditions within schools. Longitudinal components added in these studies (e.g., students followed over time) allow researchers to assess treatment effects in average rates of change (e.g., linear or quadratic). We provide methods for a priori power analysis in three-level…

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…

This paper presents the results of an experiment conducted to assess the affects of teaching recursion in two disjoint, non-consecutive units of instruction. One group of students was taught basic and advanced recursion topics in four consecutive class periods, while a second group was taught recursion in two two-period blocks that were separated…

One of the signatures of scientific writing is its ability to present the claims of science as if they were "untouched by human hands." In the early years of experimental education, researchers achieved this by adopting a citational practice that led to the sedimentation of their cardinal method, the analysis of variance, and their standard for…