Purpose: A growing trend in instructional improvement efforts is the use of formative assessment informed by research-based developmental trajectories of how students gain deeper understanding of subject matter content over time. This article reports the findings of a large-scale experimental study of an innovative mathematics professional…

In the current study, two experiments were carried out: the first tested the development of derivational root and word-pattern morphological awareness in Arabic; the second tested morphological processing in Arabic spelling. 143 Arabic native speaking children with normal reading skills in 2nd, 4th and 6th grade participated in the study. The…

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…

The equipartitioning learning trajectory (Confrey, Maloney, Nguyen, Mojica & Myers, 2009) has been hypothesized and the proficiency levels have been validated through much prior work. This study solidifies understanding of the upper level of co-splitting, which has been redefined through further clinical interview work (Corley, Confrey &…

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.…