Does Compulsory School Attendance Affect Schooling and Earnings?

This paper presents evidence showing that individuals' season of birth is related to their educational attainment because of the combined effects of school start age policy and compulsory school attendance laws. In most school districts, individuals born in the beginning of the year start school at a slightly older age, and therefore are eligible to drop out of school after completing fewer years of schooling than individuals born near the end of the year. Our estimates suggest that as many as 25 percent of potential dropouts remain in school because of compulsory schooling laws. We estimate the impact of compulsory schooling on earnings by using quarter of birth as an instrumental variable for education in an earnings equation. This provides a valid identification strategy because date of birth is unlikely to be correlated with omitted earnings determinants. The instrumental variables estimate of the rate of return to education is remarkably close to the ordinary least squares estimate, suggesting that there is little ability bias in conventional estimates of the return to education. The results also imply that individuals who are compelled to attend school longer than they desire by compulsory schooling laws reap a substantial return for their extra schooling.