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 percentiles lower in grade eight. In fact, data from Canada and the United States show that the youngest members of each cohort are even less likely to attend university.