What Have Researchers Learned from Project STAR?

Project STAR was a large-scale randomized trial of reduced class sizes in grades K-3. Because of the scope of the experiment, it has been used in many policy discussions. For example, the California state-wide Class Size Reduction was justified in part on the successes of Project STAR. Recent (failed) proposals for Federal assistance for class size reductions in the Senate were motivated by Project STAR research. Even the recent discussion of small schools often conflates the notion of small schools and smaller classrooms. Because of the importance of Project STAR, it has been studied by many scholars looking at a wide variety of outcomes and even exploiting the randomization using its variation to understand variations in inputsother aspects of the education production function that do not directly relate to class size. This paper provides an overview of the academic literature using the Project STAR experiment.