Date of Award

August 2017

Degree Type


Degree Name

Doctor of Philosophy



First Advisor

Scott J. Adams


August 2017




Mehrnoush Motamedi

The University of Wisconsin-Milwaukee, 2017

Under the Supervision of Professor Scott Adams

The goal of this dissertation is to apply empirical methodologies to analyze various topics in economics of education and health economics, which have clear policy implications.

Chapter 1 presents evidence of heterogeneous labor market returns for children depending on the time intervals between sibling births. My empirical strategy exploits exogenous variation in child spacing stemming from whether there are twins in the family and an age difference between the mother and the father. Results show significant negative effects of spacing in children from well-resourced families, but I observe positive and insignificant effects of birth spacing on children’s labor market earnings in the lower stratum.

Chapter 2 provides evidence of whether child spacing affects the likelihood of engaging in certain risky behaviors. Using data from the National Longitudinal Survey of Youth–1979, I investigate the association between birth spacing and engaging in risky or deviant behaviors, such as smoking, unprotected intercourse, theft, and violence. I attempt to identify exogenous variation in in child spacing stemming from whether one has a twin and parents’ age difference, and my estimates show significant declines in engaging in risky behaviors for all these four risky activities as birth spacing increases.

In chapter 3 despite being widely accepted as a behavior damaging to one’s future, we show that among girls engaging in sex while a teenager likely has no long-term economic consequences in terms of labor market earnings. In fact, once we control for teen childbearing and educational attainment, it is significantly correlated with positive earnings. The substantial positive outcomes appear to be concentrated among girls from higher socioeconomic strata, with little significant effects among those from less advantaged backgrounds. Only a small part of this difference seems to be explained by lower birth rates among the sexually active in higher socioeconomic strata. This leaves most due to either a causal effect of teenage sexual activity, which is unlikely, or the result of unobserved characteristics (to the researchers) among those from higher socioeconomic strata who are sexually active during adolescence. From a policy standpoint, these findings suggest that promoting teenage abstinence by touting long-term economic benefits may be misguided, particularly for those ages 15-17.

Available for download on Saturday, August 31, 2019

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