New research by Visiting Scholar Philip J. Cook (Duke University) shows that children who started kindergarten late are more likely as teenagers to drop out of school and commit serious crimes than their peers. The study—which Cook co-authored with Songman Kang of Hanyang University in South Korea—compared North Carolina public school students born 60 days before and 60 days after the school cutoff date. He noted, “This research provides the first compelling evidence of a causal link between dropout and crime. It supports the view that crime outcomes should be considered in evaluating school reforms.”

Because earlier studies have established that children who enter school at an older age perform better academically than their younger classmates, a growing number of parents have delayed enrolling their children whose birthdays fall shortly before the cutoff date, seeking to gain academic and social advantages. According to Cook’s research, older students were also less likely to engage in delinquent behavior up until age 16.

However, his latest study found that after age 16, those outcomes were reversed. The students who had started school later were more likely to drop out and be convicted of a felony before age 20. As Cook explained, the explanation for this seeming contradiction lies in the age at which students may legally withdraw from school, which is 16 in North Carolina. Cook added, “If [students] were born before the cutoff date, they have just 19 months between their 16th birthday and graduation to be tempted to drop out. If they were born just after and enter school later, they have 31 months, and for some of them, it is an irresistible temptation.”

Policies that extend the length of time students must stay in school could help offset some of these negative outcomes. According to Cook, these could include stipulations as simple as requiring students to complete a certain grade or a specified number of years in school, rather than tying withdrawal to age. “Even students who would rather drop out can benefit from staying in school when they are required to do so,” Cook said. “Otherwise they are prime candidates for recruitment into a life of crime.”

Cook and Kang’s report will be published in American Economic Journal – Applied Economics. Click here to read the full press release from Duke University.