Duke 2008 | ASHE | Equity and Efficiency in Health and Healthcare

The prevalence of obesity in the United States has more than doubled in the U.S. since 1980, leading to tremendous interest in better understanding the causes and consequences of obesity. This session brings together three papers that examine the economic contributors to obesity and its various consequences. Each of the papers tackles issues of identification using either models of instrumental variables or fixed effects models to generate causal estimates of the parameters of interest.

Chad Meyerhoefer will present a paper (coauthored with John Cawley) that estimates the causal impact of obesity on health care costs. Previous literature has documented the extent to which the obese experience higher health care costs, but that differential cannot be attributed entirely to obesity – it could be due to unobserved factors that make the obese different from the non- obese. Meyerhoefer will be the first to offer estimates from models of instrumental variables (exploiting genetic variation in weight as an instrument) that document the causal impact of obesity on health care costs.

Robert Kaestner will present evidence (collaborative with Tony LoSasso and Susan Gerber) on the link between maternal obesity and child outcomes. A problem with naiive estimates of this relationship is that obese women are likely to have unobserved characteristics that are associated with poor birth outcomes. To achieve identification, Kaestner uses an IV approach exploiting as an instrument male obesity rates in the same area.

Lisa Powell will present research on the relationship between adolescent body mass index and local fast food prices and fast food restaurant availability. Panel data estimation methods are used to account for unobserved individual-level heterogeneity. This is the first study to use panel data to assess the causal impact of economic factors on adolescent BMI.

The session will also feature assessments of the papers from experienced researchers in the area: Edward Norton of UNC, Roy Wada of RAND, and Euna Han of UIC.

Overall, the session offers a complementary set of papers and knowledgeable discussants; we expect tremendous synergies between the participants and attendees.