We estimate the effects of relative age in kindergarten using data from an experiment where children of the same age were randomly assigned to different kindergarten classmates. We exploit the resulting experimental variation in relative age in conjunction with variation in expected kindergarten entry age based on birth date to account for…

The authors examined long-term outcomes for children who experienced delayed entry to kindergarten or kindergarten retention. They used a cohort of 6,841 students to compare these groups to each other and typically progressing peers. First, the authors compared the groups on demographic and early childhood variables. For the long-term school-based…