April 20-21, 2017
Ali Moghtaderi, George Washington University, and Avi Dor, George Washington University and NBER
Immunization can cause moral hazard by reducing the cost of risky behaviors. In this study, Moghtaderi and Dor examine the effect of HPV vaccination for cervical cancer on participation in the Pap test, which is a diagnostic screening test to detect potentially precancerous and cancerous process. It is strongly recommended for women between 21-65 years old even after taking the HPV vaccine. A reduction in willingness to have a Pap test as a result of HPV vaccination would signal the need for public health intervention. The HPV vaccination is recommended for women age eleven to twelve for regular vaccination or for women up to age 26 not vaccinated previously. The researchers present evidence that probability of vaccination changes around this threshold. They identify the effect of vaccination using a fuzzy regression discontinuity design, centered on the recommended vaccination threshold age. The results show no evidence of ex ante moral hazard in the short-run. Sensitivity analyses using alternative specifications, subsamples, and bandwidths are in general agreement. The estimates show that women who have been vaccinated are actually more likely to have a Pap test in the short-run, possibly due to increased awareness of its benefits.
John Cawley, Cornell University and NBER; Euna Han, Yonsei University; Jiyoon Kim, University of Michigan; and Edward C. Norton, University of Michigan and NBER
Estimating peer effects is notoriously difficult because of the reflection problem and the endogeneity of peer group formation. Cawley, Han, Kim, and Norton test for peer effects in obesity in a novel way that addresses these challenges. They address the reflection problem by using the alter's genetic risk score for obesity, which is a significant predictor of obesity, is determined prior to birth, and cannot be affected by the behavior of others. They address the endogeneity of peer group formation by examining peers who are not chosen: full siblings. Using data from the National Longitudinal Survey of Adolescent Health, the researchers find evidence of positive peer effects in weight and obesity; having a sibling with a high genetic predisposition raises one's risk of obesity, even controlling for one's own genetic predisposition to obesity. Implications of the findings include that peer effects may be an explanation for continued worldwide increases in weight, and that, because of social multipliers, the cost-effectiveness of obesity treatment and prevention programs may have been underestimated.
Adam Leive, University of Virginia
In this paper, Leive investigates how status affects health by comparing mortality between gold and silver medalists in Olympic Track and Field. Contrary to conventional wisdom, winners die over two years earlier than losers. Analysis of individual Census records of each U.S. athlete and his parents suggests that income is the key mechanism: losers pursued higher-paying occupations than winners after the Olympics, while parental earnings in childhood were similar. The results suggest that how people respond to pivotal life events can produce long-lasting consequences for health.
Christopher Carpenter, Vanderbilt University and NBER, and Emily C. Lawler, Vanderbilt University
Carpenter and Lawler study the direct and spillover effects of state requirements that middle school youths obtain a tetanus, diphtheria, and pertussis (Tdap) booster prior to middle school entry. These mandates increased vaccine take-up by 29 percent and reduced pertussis (whooping cough) incidence in the population by a much larger 53 percent due to herd immunity effects. The researchers also document cross-vaccine spillovers: the mandates increased adolescent vaccination for meningococcal disease and human papillomavirus (which is responsible for 98 percent of cervical cancers) by 8-34 percent, with particularly large effects for children from low SES households.
Daniel S. Grossman and Umair Khalil, West Virginia University
Grossman and Khalil explore the existence of social interactions in program participation within small neighborhood networks. Their population of interest is pregnant women and their participation in Medicaid during pregnancy. Using geographically detailed data, the researchers show that a pregnant mother is substantially more likely to participate in Medicaid, if recently pregnant mothers on her exact census block also received Medicaid benefits. To deal with endogenous sorting into neighborhoods, They only compare mothers across small neighborhoods within a broader geographic area defined as an agglomeration of nearby census blocks. The reflection problem is avoided by restricting peer groups to only mothers who have recently given birth. They also document substantial heterogeneity in the estimated network effect across various dimensions. Furthermore, increased Medicaid participation seems to translate into healthier behavior among pregnant women with earlier and more intensive participation in prenatal care.
Willa H. Friedman, University of Houston, and Nicholas Wilson, Reed College
A fundamental puzzle about human behavior is the low level of household investment in preventive health inputs. Friedman and Wilson conducted a field experiment testing advertising strategies designed to increase demand for a life-saving preventive health technology. Offering compensation of US$10 conditional on completing a counseling session for the technology tripled uptake. Framing the basic advertisement using the statement, "Are you tough enough?", doubled uptake. Suggestive evidence indicates these advertisements reduced procrastination. The study appears to be the first showing that a small conditional cash transfer for a one-time health clinic visit can improve individual investment in preventive health inputs.