Good research in education is defined as randomized experiments. For a study to be eligible to earn the highest possible rating from the What Works Clearinghouse (Meets WWC Standards without Reservations), the arbiter of what constitutes rigorous research within the U.S. Department of Education, it must use random assignment to determine group…

School-based evaluations of interventions are increasingly common in education research. Ideally, the results of these evaluations are used to make evidence-based policy decisions for students. However, it is difficult to make generalizations from these evaluations because the types of schools included in the studies are typically not selected…