The purpose of this study is to evaluate the implementation and impacts of the Building Assets, Reducing Risks (BARR) model in its first year of implementation in 66 schools across the U.S. and to document scale-up progress during the Investing in Innovation (i3) grant period (2017-2021). The impact evaluation included 21,529 9th grade students…

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.…