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Abstract:
We use panel data techniques and information on state-level Food Stamp Program (FSP) characteristics to obtain unbiased estimates of the impact of FSP participation on weight status and health care spending among non-elderly adults. Our results suggest that program participation by women leads to a 5.9 percent (p=.07) increase in their likelihood of overweight and obesity, which is smaller than previous estimates, and to higher medical expenditures. The direct effect of FSP participation on medical spending through higher discretionary income is significantly larger than the indirect effect through changes in weight status.

Food Stamp Program, Obesity, Medical Expenditures, Panel Data

Abstract:
Much of the debate surrounding Direct-to-Consumer Advertising (DTCA) of pharmaceuticals centers on whether DTCA conveys useful information to consumers or indiscriminately increases requests for the advertised medication. By identifying how DTCA changes the shape of the demand curve for antidepressants, we seek to infer the promotional objectives of manufacturers. Using data from the 1996-2003 Medical Expenditure Panel Survey (MEPS), we find that advertising shifts the demand curve for antidepressants outward and rotates it counter-clockwise. DTCA increases the probability that an individual will initiate use of antidepressants, particularly when out-of-pocket medication costs are low, but does not necessarily increase utilization levels among those already taking antidepressants. This is consistent with a promotional campaign that seeks to alert consumers to the product's existence, but conveys no real information that would allow them to learn their true match with the product.

pharmaceutical demand, DTCA, MEPS

Abstract:
Consumers' price responsiveness is central to current reform proposals to address rapidly escalating health care costs, but the best available estimates of price elasticities of demand are now more than 25 years old. We seek to provide more current estimates of the demand for both mental and physical health treatment using a health care demand model that incorporates the relevant costs influencing consumption decisions, including out-of-pocket payments (cost-sharing) for ambulatory services, out-of-pocket prescription drug costs, and insurance premiums. Following Ellis (1986) and Ellis and McGuire (1986), we use consumers' out-of-pocket payments to derive theoretically appropriate expected end-of-year prices. The demand model is estimated using the 1996-2003 Medical Expenditure Panel Survey (MEPS), a nationally representative survey of the U.S. civilian, non-institutionalized population. We address the potential endogeneity of expected end-of-year prices and health insurance coverage (or adverse selection) by estimating a correlated random effects specification (Chamberlain, 1980). This allows us to relax the untenable assumption of standard random effect models that price and health insurance are uncorrelated with unobserved individual attributes. We find that the price responsiveness of ambulatory mental health visits has decreased substantially in the last 30 years and is now slightly less elastic than visits for physical health problems. However, the demand for both mental health and non-mental prescription drugs is substantially more price elastic. We discuss the implications of our results.

Health Care Demand, Panel Data, Mental Health

Abstract:
To combat childhood overweight in the U.S., which has risen dramatically in the past three decades, many medical and public health organizations have called for students to spend more time in physical education (PE) classes. This paper is the first to examine the impact of state PE requirements on student physical activity and overweight. It also exploits variation in state laws as quasi-natural experiments in order to estimate the causal impact of PE on student activity and weight. We study nationwide data from the Youth Risk Behavior Surveillance System for 1999, 2001, and 2003 merged with data on state minimum PE requirements from the 2001 Shape of the Nation Report.

We find that high school students with a binding PE requirement report an average of 31 additional minutes spent physically active in PE class. Our results also indicate that additional PE time raises the number of days per week that girls report having exercised vigorously or having engaged in strength-building activity.

We find no evidence that PE lowers BMI or the probability that a student is overweight. We conclude that raising PE credit requirements may make girls more physically active overall but that there is not yet the scientific base to declare raising PE requirements an anti-obesity initiative for either boys or girls.

obesity, physical activity, education, instrumental variables

Abstract:
To combat childhood overweight, which has risen dramatically in the past three decades, many medical and public health organizations have called for students to spend more time in physical education (PE) classes. This paper is the first to exploit state PE requirements as quasi-natural experiments in order to estimate the causal impact of PE on student activity and weight. We study nationwide data from the YRBSS for 1999, 2001, and 2003 merged with data on state minimum PE requirements from the 1994 and 2000 School Health Policies and Programs Study and the 2001 Shape of the Nation Report.

We find that certain state regulations are effective in raising the number of minutes during which students are active in PE. Our results also indicate that additional PE time raises the number of days per week that students report having exercised or engaged in strength-building activities, but lowers the number of days in which students report light physical activity. PE time has no detectable impact on youth BMI or the probability that a student is overweight. We conclude that while raising PE requirements may make students more active by some (but not all) measures, there is not yet the scientific base to declare raising PE requirements an anti-obesity initiative.

Abstract:
We derive a joint continuous/censored commodity demand system for panel data applications. Unobserved heterogeneity is controlled for using a correlated random effects specification and a generalized method of moments framework used to estimate the model. While relatively small differences in elasticity estimates are found between a flexible random effects specification and one that restricts the random effect coefficient to be time invariant, larger differences are observed when comparing the flexible model to a pooled cross-sectional estimator. The results suggest the limited ability of such estimators to control for preference heterogeneity and unit-value endogeneity leads to parameter bias.

almost ideal demand system, censoring, generalized method of moments, panel data

Abstract:
In this paper we derive a joint continuous/censored demand system suitable for the analysis of commodity demand relationships using panel data. Unobserved heterogeneity is controlled for using a correlated random effects specification and a Generalized Method of Moments framework used to estimate the model in two stages. While relatively small differences in elasticity estimates are found between a flexible specification and one that restricts the relationship between the random effect and budget shares to be time invariant, larger differences are observed between the most flexible random effects model and a pooled cross sectional estimator. The results suggest the limited ability of such estimators to control for preference heterogeneity and unit value endogeneity leads to parameter bias.

censoring, almost ideal demand system, random effects, GMM

Abstract:
Childhood overweight has risen dramatically in the United States during the past three decades. The search for policy solutions is limited by a lack of evidence regarding the effectiveness of state policies for increasing physical activity among youths. This paper estimates the correlation of student physical activity with a variety of state policies. We study nationwide data on high school students from the Youth Risk Behavior Surveillance System for 1999, 2001, and 2003 merged with data on state policies from several sources. We control for a variety of characteristics of states and students to mitigate bias due to the endogenous selection of policies, but we conservatively interpret our results as correlations, not causal impacts. Two policies are positively correlated with participation in physical education (PE) class for both boys and girls: a binding PE unit requirement and a state PE curriculum. We also find that state spending on parks and recreation is positively correlated with two measures of girls' overall physical activity.

Abstract:
This paper explores linkages between the demand for health care providers and the consumption of food, non-food goods, and leisure in Vietnam, using a mixed continuous/discrete dependent variable model. Cross-price elasticities calculated from the model suggest there are strong substitution effects between health care, leisure, and certain commodities. The model allows us to explore the implications of replacing user fees with alternative forms of health care finance, such as commodity taxes. In particular, the results suggest financing public health care services with a non-food sales tax rather than user fees would be more progressive and would improve access to care.

Abstract:
Airframe fatigue has emerged as a primary determinant of tactical aircraft service life. To investigate the impact of various operational scenarios on airframe fatigue and aircraft stocks, we develop an econometric model of fatigue and arrested landing accumulation for U.S. Naval aircraft. Model forecasts suggest that fatigue related attrition threatens to reduce inventories below the level needed to meet operational commitments before planned replacements are available. Changes to training regimes could mitigate the shortfall, but it is likely that acquisition schedules will have to be accelerated, or current service life extension programs expanded to maintain inventories in the future.

Aircraft Procurement, Airframe Fatigue, U.S. Navy