It is well known that exposure to lead has numerous adverse effects on behavior and development, but little work to date has examined the cumulative lifetime effect of such exposure on aspects of behavior. In this paper, I use data on two cohorts of children from the NLSY to investigate the effect of early childhood lead exposure on behavior problems from childhood through early adulthood. I find large negative consequences of early childhood lead exposure, in the form of an unfolding series of adverse behavioral outcomes ranging from behavior problems as a child, to pregnancy and aggression as a teen, and to criminal behavior as a young adult. Estimated elasticities of these behaviors with respect to lead range between 0.1 and 1.0. This evidence suggests that, by increasing impulsivity and aggression, even moderate exposure to lead in early childhood can have substantial and persistent adverse effects on individual behavior. Moreover, such moderate exposure was the norm for residents of the United States born between the 1950s and the early 1980s.
It is now widely accepted that childhood exposure to even low levels of lead can adversely affect neurodevelopment, behavior, and cognitive performance. Using individual-level data on childhood lead levels and test scores in Massachusetts, this paper investigates the link between lead levels in early childhood in the 1990s and student test scores in elementary school in the 2000s. Massachusetts is well-suited for this analysis both because it has been a leader in the reduction of childhood lead levels for four decades, and also because it has mandated standardized achievement tests in public elementary schools for almost two decades. Panel data analysis is conducted at the school-cohort level for children born between 1991 and 2000 and attending 3rd and 4th grades between 2000 and 2009 at more than 1,000 public elementary schools in Massachusetts. Elevated levels of blood lead in early childhood are shown to adversely impact standardized test performance, even when controlling for community and school characteristics. Accordingly, public health policy that reduced childhood lead levels in the 1990s was responsible for modest but statistically significant improvements in test performance in the 2000s, with particular benefits for children in low-income communities.
Childhood lead exposure can lead to psychological traits that are strongly associated with aggressive and criminal behavior. In the late 1970s in the United States, lead was removed from gasoline under the Clean Air Act. I use the state-specific reductions in lead exposure that resulted from this removal to identify the effect of childhood lead exposure on crime rates. The elasticity of violent crime with respect to childhood lead exposure is estimated to be 0.8, and this result is robust to numerous sensitivity tests. Mixed evidence supports an effect of lead exposure on murder rates, and little evidence indicates an effect of lead on property crime. Overall, I find that the reduction in childhood lead exposure in the late 1970s and early 1980s was responsible for significant declines in violent crime in the 1990s and may cause further declines in the future. Moreover, the social value of the reductions in violent crime far exceeds the cost of the removal of lead from gasoline.
This Article investigates the effects of malpractice liability on the specialty of obstetrics and gynecology. The authors combine rich data from a survey of 1,476 physicians with detailed measures of liability pressure to assess the effects of the liability environment on physician behavior. The analysis reveals important inconsistencies between alleged effects and actual effects. On the one hand, physicians report having made substantial changes to their practice in response to the general malpractice environment and to liability pressures. But on the other hand, regression analysis finds that the direct effects on actual physician income and productivity are less clear. The evidence suggests that rising malpractice premiums may lead to practice reductions in the short run, but that in the long run they lead to a specialization effect by which some physicians focus more on obstetrics and others focus more on gynecological surgery. Thus, the analysis suggests that while the liability environment has had modest effects on the specialty of obstetrics and gynecology, these effects appear to fall short of a malpractice-induced “crisis.”
This paper 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. The paper finds that both money and non-money prices adjust: female OB/GYNs charge higher fees and also have longer waiting times. Furthermore, 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.
The financial aid system imposes an implicit asset tax that is prevalent and substantial. Facing this tax, rational families should reduce their total assets and shelter assets in protected categories. I find that the tax induces a 7% reduction in total assets, a result in line with the literature. Furthermore, I find evidence that families reallocate assets into sheltered retirement accounts. The paper provides further evidence that the financial aid tax reduces asset accumulation and prompts a reconsideration of the simple “higher tax, lower assets” story. It provides the first evidence that families may be engaging in a rational reallocation of their asset portfolio.
In many academic settings, undergraduate economics majors are asked to do an independent project or thesis in their final year. Because doing research is very different from learning economics in a classroom, students are frequently unprepared for this endeavor. This article describes a seminar course intended to ease this transition by preparing students to embark on such a project. The first goal of the course is to assist students in developing a sound economic research project. The second goal is to help them develop the research skills to execute their project. In essence, the course is an abbreviated and accelerated version of some of the learning that takes place alongside the standard curriculum in graduate school. The article describes a course that has been designed for a liberal arts setting, and also discusses other possible variations.