Mai Noguchi Hubbard

Ph.D. Candidate

Department of Economics

The Effect of Mothers' Employment and Child Care Decisions on the Body Mass Status of Young Children (Job Market Paper)

Abstract:

Childhood obesity rates have increased dramatically in the United States since the late 1970s. During the same time period, the nation has witnessed an upward trend in women's labor force participation and in the use of child care. Despite a large body of empirical research on the impact of environmental, behavioral, and societal factors on obesity, surprisingly little attention has been devoted to examining the relationship between maternal employment, non-parental child care, and childhood obesity. I analyze the effects of mothers' employment and child care decisions on several alternative measures of children's body mass status in the first, third, and fifth grades using the Early Childhood Longitudinal Survey-Kindergarten Cohort. Employment and child care decisions and child health over several years are modeled in a dynamic framework, and empirically evaluated using a random effects joint estimation technique that models the unobserved heterogeneity influencing employment and child care demand, and child's health production. I find that maternal employment over time, significantly decreases children's probability of being obese by 5.4 percentage points and BMI-percentile-for-sex-and-age by more than 3 percentile points. I also find that for mothers working full-time, using child care significantly increases children's risk of being obese by 3.7 percentage points and risk of being overweight by 0.5 percentage points

Did Kicking the Habit Make Us Fat? The Impact of Smoking on the Likelihood of Being Overweight and Obese (Submitted; Joint with P.M. Lance and G. Angeles)

Abstract:
Two of the most pronounced health trends in the United States in the past several decades have been the precipitous decline in cigarette smoking and the striking increase in the proportions of the population that are overweight or obese. Nonetheless, relatively little research in the social sciences examines the potential link between the two developments, despite that obvious possibility given their dramatic, concurrent nature. Further, the prevailing theoretical explanations for the obesity epidemic in
the economics literature, which quite sensibly focus essentially on caloric intake and energy expenditure, assign little role to the decline in smoking. However, the notion that declining cigarette smoking was a significant causal contributor to the obesity epidemic is consistent with these other explanations and in some sense can even reinforce them. We estimate the causal effect of smoking on the probabilities of being obese and overweight using a flexible semi-nonparametric full information instrumental variables, random effects strategy. We find that smoking significantly reduces the probability of these outcomes, and that failure to control for the endogeneity of smoking leads to underestimation of the impact of smoking on the probability of being obese or overweight. Our results contribute to a small but growing body of research that suggests that the largely successful campaign to reduce smoking in the United States may have played a significant role in the emergence of the obesity epidemic.

The Role of Income and Acculturation on Adolescent Obesity (UNC Working Paper; Joint with D. Gilleskie)

Abstract:

A review of the current literature indicates that factors such as income and acculturation status have significant effects on the body mass of adolescents. Much of the existing research on this topic however, has not examined the potential difference in the effect of income on adolescents' body masses by acculturation status. Furthermore, the mechanisms by which these factors affect health are not yet clearly understood. In this analysis, we attempt to assess differences in the effect of income by acculturation status on various health inputs, and evaluate the subsequent impact of inputs on adolescent's body weight. Specifically, we estimate the impact of income on food consumption and engagement in activities by acculturation status and then evaluate the effect of these inputs on a child's body mass.

How do we know if a program made a difference? A helicopter tour of the econometrics of program evaluation (UNC Carolina Population Center Working Paper; Joint with P.M. Lance and G. Angeles)

Abstract:

This paper offers a survey of popular econometric methods for recovering statistically valid estimates of the impact of human resource programs. The challenge in doing so is that in the real world operational setting program participation is often not random. Individuals consciously decide whether to enroll. Their enrollment decision is typically influenced by their observed and unobserved characteristics, which might also influence the outcome of interest. Non-participants thus do not form a valid experimental control for participants for the purpose of determining what outcomes participants might have experienced in the absence of the program (and vice-versa). We begin by characterizing the program evaluation problem and then provide a survey of the various econometric methods typically applied in response to it. Our survey focuses on 'classes' of estimation strategies. For each, we emphasize data requirements and assumptions, sources of identification and interpretation of results. Our goal is to offer an accessible and intuitively appealing guide to the tools available from the econometrics tradition.