The impact of lead exposure on crime and health, and an analysis of the market for physicians: Three essays.

摘要

Childhood lead exposure can reduce IQ, cause attention impairment, and increase impulsive and aggressive behavior. These childhood deficits are strongly associated with a higher likelihood of criminal behavior in adulthood. Chapter 1 uses sharp reductions in lead exposure resulting from the removal of lead from gasoline under the Clean Air Act to identify how childhood lead exposure affects adult crime rates. I find that the reduction in childhood lead exposure in the late 1970s and early 1980s accounts for approximately one-third of the drop in crime in the 1990s. The effect of the removal of lead from gasoline is identified with detailed data on gasoline consumption and is validated with independent data on air lead concentrations. The estimates of the paper imply that the total removal of lead from gasoline under the Clean Air Act may eventually cause large declines in crime rates between 1993 and 2013.;Chapter 2 investigates how prenatal lead exposure affects reproductive outcomes. I find that prenatal lead exposure increases infant mortality and the likelihood of low birth weight. The complete phaseout of leaded gasoline is associated with 3--4% reductions in infant mortality and low birth weight. I conclude that even moderate levels of prenatal lead exposure can significantly harm infant health and that the removal of lead from gasoline produced small but significant benefits for reproductive and infant health.;Chapter 3 analyzes how the imperfectly competitive market for Obstetricians and Gynecologists (OB/GYNs) clears in the face of an excess demand for female OB/GYNs. This excess demand results from the convergence of three factors: (i) all OB/GYN patients are women, (ii) many women prefer to be treated by a female OB/GYN, (iii) only a small portion of OB/GYNs are female. I find that both money and non-money prices adjust, and that these effects are mediated by institutional structure. In contract settings in which money prices are rigid (i.e. managed care), waiting times are more likely to adjust, and in settings in which money prices are more flexible, the reverse occurs. Lastly, female OB/GYNs do close the gender gap in weekly income significantly.