Does Age at Enrollment in first Grade Affect Children's cognitive Test Scores

We use data from the National Longitudinal Survey of Youth Mother-Child Files to estimate the effect of age at enrollment in first grade on eight to eleven year old children's cognitive test scores and behavior problems. We find that children who enroll in first grade at a young age score higher on cognitive tests and have fewer behavior problems than children of the same age who enroll at an older age. This is mainly because children who enroll earlier have had more schooling than their same-aged peers who enrolled later. We also find that among children with the same amount of schooling, those who enrolled at a younger age have higher verbal scores than those who enrolled at an older age. This is because they were exposed to schooling at a younger age. We assess the extent to which early gains in test scores attributable to enrolling at a younger age decline as children progress through school and the extent to which the benefit of early enrollment is due to family background characteristics.