In an effort to reduce viral transmission, many schools are planning to reduce class size if they have not reduced it already. Yet the effect of class size on transmission is unknown. To determine whether smaller classes reduce school absence, especially when community disease prevalence is high, we merge data from the Project STAR randomized…

Although experimental results indicate that smaller classes promote higher achievement in early elementary school, the broader literature on class-size effects is inconclusive. This seeming contradiction raises questions about the generalizability of experimental evidence, an issue that this article addresses by examining the effects of class size…

Most teachers and the public believe that children in kindergarten and the primary grades benefit from small classes because of children's need for individualized instruction and teacher attention. This report, part of a comprehensive policy study of early childhood education, presents a review of the research on the effect of class size on…