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.
ability
During the Vietnam draft priority for military service was randomly
assigned to draft-age men in a series of lotteries. However, many men
managed to avoid military service by enrolling in school and obtaining an
educational deferment. This paper uses the draft lottery as a natural
experiment to estimate the return to education and the veteran premium.
Estimates are based on special extracts of the Current Population Survey
that the Census Bureau assembled for 1979 and 1981-85. The results suggest
that an extra year of schooling acquired in response to the lottery is
associated with 6.6 percent higher weekly earnings. This figure is about
10 percent higher the OLS estimate of the return to education for this
sample, which suggests there is little ability bias in conventional
estimates of the return to education. Our findings are robust to a variety
of "alternative assumptions about the effect of veteran status on earnings.