The Persistence of Early Childhood Maturity: International Evidence of Long-Run Age Effects*

A continuum of ages exists at school entry due to the use of a single school cutoff date—making the “oldest” children approximately 20 percent older than the “youngest” children. We provide substantial evidence that these initial maturity differences have long-lasting effects on student performance across OECD countries. In particular, the youngest members of each cohort score 4–12 percentiles lower than the oldest members in grade four and 2–9 …