Mother's education and the intergenerational transmission of human capital: Evidence from college openings
Currie and Moretti ask, Does increased maternal education result in increased infant health, and on a series of other factors that are likely to influence infant health? The goal of their analysis is to identify a causal effect of education on a set of non-labor market outcomes as a way of demonstrating positive externalities associated with education.
They focus on four key pathways though through which education might improve the health of infants:
- Prenatal care
- Marriage to higher earning men
- Inducement of woman to have healthier behavior (i.e., not smoking)
- Effect of education on fertility
In particular, they look at outcomes in terms of birth weigh and gestational age of children.
They use data taken from Vital Statistics Natality records from 1970 to 1999 a custom created dataset of college openings, and US Census PUMS data and the National Longitudinal Study of Youth for robustness checks.
They analysis focuses on two instrumental variables:
- The number of 2-year colleges that existed in the women's county in the year they were 17 years old divided by the number of 18-22 year olds in that county (expressed in 1000s).
- The number of 4-year colleges that existed in the women's county in the year they were 17 years old divided by the number of 18-22 year olds in that county (expressed in 1000s).
Their analysis includes county-year fixed effects to control for all observed and unobserved variation due to location in a particular county at a particular time.
They find that higher maternal education improves child "quality" in terms of their two outcomes and estimate that an additional year of education reduces the incidence of low birth weight by approximately 10 percent, and reduces the incidence of preterm birth by 6 percent.
They also evaluate and speak to two major threats to validity:
- An assumption that women are not mobile and that the county they give birth in is the one they were in at 17.
- Geographic location of new colleges is not likely to be random and colleges are like to be opening in places where education is already increasing or is expected to increase.