Computers have changed the landscape of scientific research in profound ways. Technology has always played an important role in scientific experimentation--through the development of increasingly sophisticated tools, the measurement of elusive quantities, and the processing of large amounts of data. However, the advent of social networking and the…

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.…

Value-added models, which rate schools for effectiveness while taking into account the poverty and other socioeconomic status of the students, are generating increased interest. This paper describes the use of one such model to evaluate whether school ratings changed when three new programs were introduced: the "Target Teach" curriculum…