Most evaluations of education policies focus on their mean impacts; when distributional effects are investigated it is usually by comparing mean impacts across demographic subgroups. We argue that such estimates may overlook important treatment effect heterogeneity; in order to appreciate the full extent of a policy's distributional impacts one…

Understanding the effects of class size reduction (CSR) has been an enduring issue in education. For the past 3 decades, Project STAR has stimulated research and policy discussions regarding the effects of CSR on a variety of outcomes. Schanzenbach (2007) reviewed STAR studies and concluded that small classes improved student academic outcomes.…

The California class size reduction program provided schools with cash rewards for K-3 classes of 20 or fewer students. I show how program rules made it possible for schools to save money by using mixed-grade classes to meet class size reduction obligations while maintaining larger average class sizes. I also show that this smoothing of students…

Intuitively, class size reduction is a good idea. Parents support it because it means that their children will receive more individual attention from teachers. Teachers like it for the same reason and also because it creates a more manageable workload. It is generally assumed that the fewer students in a class, the better they will learn and the…