Class Size, Student Disruption, and Academic Achievement

A large literature finds mixed evidence on the direction and magnitude of the educational return to class size. A seminal paper by Lazear (2001. “Educational Production.” Quarterly Journal of Economics 116 (3): 777–803) attempted to reconcile these disparate findings by developing a theoretical model that allowed the return to class size to vary by the level of classroom disruption. In this study, we present new evidence on this topic. Our estimates indicate that larger class sizes reduce test scores in disruptive environments but not in settings where there is little disruption. Even though we find evidence consistent with the Lazear hypothesis, the estimates are small in magnitude and suggest that marginal changes in class size are not likely to be a primary factor in explaining variation in high-school aged student success, as measured by test scores.