Theories regarding the long-term effects of educational interventions are often assumed, but rarely tested using experimental methods. In the following commentary, we argue that the shortage of randomized control trials with long-term follow-up presents serious problems for the field, as it hampers our ability to develop educational programs that…

This policy brief draws on research and evaluations of efforts in Tennessee, California, and Wisconsin to describe different approaches to reducing class size in kindergarten through third grade. Tennessee implemented a randomized experiment to investigate the effectiveness of smaller classes; California used a statewide approach; and Wisconsin…