Getting Inside the "Black Box" of Head Start Quality: What Matters and What Doesn't?

Critics of Head Start contend that many programs spend too much money on programs extraneous to education. On the other hand, Head Start advocates argue that severely disadvantaged children need a broad range of services. Given the available evidence, it has been impossible to assess the validity of these claims. In this study, we match detailed administrative data with data on child outcomes from the National Longitudinal Survey of Youth 1979, including test scores, behavior problems, and grade repetition. We find that former Head Start children have higher reading scores and are less likely to have been retained in grade where Head Start spending was higher. Holding per capita expenditures constant, children in programs that devoted higher shares of their budgets to education and health have fewer behavior problems and are less likely to have been retained in grade. However, when we examine specific educational inputs holding per capita expenditures constant, only pupil/teacher ratios matter.

Air Pollution and Infant Health: What Can We Learn From California's Recent Experience

We examine the impact of air pollution on infant death in California over the 1990s. Our work offers several innovations: First, many previous studies examine populations subject to far greater levels of pollution. In contrast, the experience of California in the 1990s is clearly relevant to current debates over the regulation of pollution. Second, many studies examine a few routinely monitored pollutants in isolation, generally because of data limitations. We examine four criteria' pollutants in a common framework. Third, we develop an identification strategy based on within zip code variation in pollution levels that controls for potentially important unobserved characteristics of high pollution areas. Fourth, we use rich individual-level data to investigate effects of pollution on infant mortality, fetal deaths, low birth weight and prematurity in a common framework. We find that the reductions in carbon monoxide (CO) and particulates (PM10) over the 1990s in California saved over 1,000 infant lives. However, we find little consistent evidence of pollution effects on fetal deaths, low birth weight or short gestation.

The Economic Value of Teeth

Healthy teeth are a vital and visible component of general well-being, but there is little systematic evidence to demonstrate their economic value. In this paper, we examine one element of that value, the effect of oral health on labor market outcomes, by exploiting variation in access to fluoridated water during childhood. The politics surrounding the adoption of water fluoridation by local water districts suggests exposure to fluoride during childhood is exogenous to other factors affecting earnings. We find that women who resided in communities with fluoridated water during childhood earn approximately 4% more than women who did not, but we find no effect of fluoridation for men. Furthermore, the effect is almost exclusively concentrated amongst women from families of low socioeconomic status. We find little evidence to support occupational sorting, statistical discrimination, and productivity as potential channels of these effects, suggesting consumer and employer discrimination are the likely driving factors whereby oral health affects earnings

Cognitive and Noncognitive Peer Effects in Early Education

We examine peer effects in early education by estimating value-added models with school fixed effects that control extensively for individual, family, peer, and teacher characteristics to account for the endogeneity of peer group formation. We find statistically significant and robust spillover effects from preschool on math and reading outcomes, but statistically insignificant effects on various behavioral and social outcomes. We also find that peer externalizing problems, which most likely capture classroom disturbance, hinder cognitive outcomes. Our estimates imply that ignoring spillover effects significantly understates the social returns to preschool

Pollution, Health, and Avoidance Behavior: Evidence from the Ports of Los Angeles

A pervasive problem in the literature on the health costs of pollution is that optimizing individuals may compensate for increases in pollution by reducing their exposure to protect their health. This implies that estimates of the health effects of pollution may vastly understate the full welfare effects of pollution, particularly for individuals most at risk who have the greatest incentive to adopt compensatory behavior. Furthermore, using ambient monitors to approximate individual exposure to pollution may induce considerable measurement error. We overcome these issues by estimating the short run effects of ozone on respiratory related health conditions using daily boat arrivals and departures into the two major ports of Los Angeles as an instrumental variable for ozone levels. While daily variation in boat traffic is a major contributor to local ozone pollution, time-varying pollution due to port activity is arguably a randomly determined event uncorrelated with factors related to health. Instrumental variable estimates are significantly larger than OLS estimates, indicating the importance of accounting for avoidance behavior and measurement error in understanding the full welfare effects from pollution.

Days of Haze: Environmental Information Disclosure and Intertemporal Avoidance Behavior

In this paper, we investigate the dynamics of informational regulatory approaches by analyzing the impact of smog alerts issued on consecutive days on discretionary outdoor activities in Southern California. Short-run adjustments to transitory risk entail costs that are likely to influence the set of evasive actions pursued by those at risk. Our results confirm that the cost of intertemporally substituting activities is increasing over time: when alerts are issued on two successive days, any response on the first day has largely disappeared by the second day. Small reprieves from alerts, however, reset these costs. Our findings imply that a time-varying decision rule that accounts for multiple day air quality forecasts may improve social welfare.

Does Pollution Increase School Absences?

We examine the effect of air pollution on school absences using unique administrative data for elementary and middle school children in the 39 largest school districts in Texas. These data are merged with information from monitors maintained by the Environmental Protection Agency. To control for potentially confounding factors, we adopt a difference-in-difference-in differences strategy, and control for persistent characteristics of schools, years, and attendance periods in order to focus on variations in pollution within school-year-attendance period cells. We find that high levels of carbon monoxide (CO) significantly increase absences, even when they are below federal air quality standards.

Temperature and the Allocation of Time: Implications for Climate Change

In this paper we estimate the impacts of climate change on the allocation of time using econometric models that exploit plausibly exogenous variation in daily temperature over time within counties. We find large reductions in U.S. labor supply in industries with high exposure to climate and similarly large decreases in time allocated to outdoor leisure. We also find suggestive evidence of short-run adaptation through temporal substitutions and acclimatization. Given the industrial composition of the US, the net impacts on total employment are likely to be small, but significant changes in leisure time as well as large scale redistributions of income may be consequential. In developing countries, where the industrial base is more typically concentrated in climate-exposed industries and baseline temperatures are already warmer, employment impacts may be considerably larger.

Air Pollution and Infant Health: Lessons from New Jersey

We examine the impact of three "criteria" air pollutants on infant health in New Jersey in the 1990s by combining information about mother's residential location from birth certificates with information from air quality monitors. In addition to large sample size, our work offers three important innovations: First, because we know the exact addresses of mothers, we select those mothers closest to air monitors to ensure a more accurate measure of air quality. Second, since we follow mothers over time, we control for unobserved characteristics of mothers using maternal fixed effects. Third, we examine interactions of air pollution with smoking and other predictors of poor infant health outcomes. We find consistently negative effects of exposure to pollution, especially carbon monoxide, both during and after birth. The effects are considerably larger for smokers than for nonsmokers as well as for older mothers. Since automobiles are the main source of carbon monoxide emissions, our results have important implications for regulation of automobile emissions.

The Impact of Pollution on Worker Productivity

Environmental protection is typically cast as a tax on the labor market and the economy in general. Since a large body of evidence links pollution with poor health, and health is an important part of human capital, efforts to reduce pollution could plausibly be viewed as an investment in human capital and thus a tool for promoting economic growth. While a handful of studies have documented the impacts of pollution on labor supply, this paper is the first to rigorously assess the less visible but likely more pervasive impacts on worker productivity. In particular, we exploit a novel panel dataset of daily farm worker output as recorded under piece rate contracts merged with data on environmental conditions to relate the plausibly exogenous daily variations in ozone with worker productivity. We find robust evidence that ozone levels well below federal air quality standards have a significant impact on productivity: a 10 ppb decrease in ozone concentrations increases worker productivity by 4.2 percent.