External Costs of Obesity

描述（由申请人提供）：成人肥胖是一个棘手的公共卫生问题。大量文献记录了美国肥胖症患病率的上升，并衡量相关的健康和会计成本。十多年前，沃尔夫和科迪茨测算出，每年因肥胖造成的医疗保健成本和工作效率损失超过680亿美元。与肥胖相关的发病率和会计成本导致经济学家和公共卫生从业人员都主张积极的公共干预。然而，衡量肥胖导致的医疗成本本身与遏制肥胖的公共行动是否合理的辩论并不密切相关。相反，体重决定的成本不是由做出这些决定的成年人承担的（以下称为外部成本）。肥胖症（潜在）补贴的一个重要机制是通过健康保险。有一个小的实证文献，旨在衡量公共健康保险的成本归因于肥胖。该文献仅关注肥胖和非肥胖成年人之间的健康支出差异，但忽略了相关的支付差异。例如，在医疗保险的情况下，这篇文献没有考虑通过税收的差异贡献，差异肥胖相关的死亡率，以及医疗保健支出的时间。在雇主提供私人保险的情况下，文献忽略了一种可能性（补偿工资差异理论所暗示的），即相对于较瘦的工人，由于他们预期的医疗支出较高，肥胖工人的保险额减少了。即使对补贴进行适当的测量，也不足以计算健康保险引起的肥胖外部性所造成的福利损失。如果补贴不能改变健康保险池中人们的行为，那么补贴只是从瘦到胖的无成本转移，不会改变社会福利。关键的问题是：在多大程度上转移到肥胖的成年人改变他们的饮食和锻炼决定的动机？外部性的福利损失与补贴的规模和体重决定对补贴的弹性成正比。我们提出三项任务：（1）从终身的角度衡量医疗保险引起的非肥胖到肥胖个体的净补贴;（2）衡量雇主提供的健康保险引起的净补贴;（3）衡量健康保险引起的补贴对体重决定的扭曲程度。

DESCRIPTION (provided by applicant): Adult obesity is a thorny public health problem. A large literature documents rising obesity prevalence in the U.S., and measures the associated health and accounting costs. Over a decade ago, Wolf and Colditz measured the health care costs and lost workplace productivity due to obesity to be over $68 billion annually. The morbidity and accounting costs associated with obesity have led economists and public health practitioners alike to advocate vigorous public intervention. However, measures of medical costs due to obesity are not, in and of themselves, germane to the debate over whether public actions to curb obesity are justified. Rather, it is the costs of body weight decisions not borne by an adult making those decisions (hereafter, external costs) that are most relevant. An important mechanism by which obesity is (potentially) subsidized is through health insurance. There is a small empirical literature aimed at measuring the cost of public health insurance attributable to obesity. This literature focuses solely on health expenditure differences between obese and non-obese adults but ignores relevant payment differences. In the case of Medicare, for example, this literature does not consider differential contributions via taxes, differential obesity-related mortality, and the timing of health care expenditures. In the case of employer provided private insurance, the literature ignores the possibility (implied by the theory of compensating wage differentials) that, relative to thinner workers, covered obese workers are reduced because of their higher expected medical expenditures. Even a proper measurement of the subsidy is not enough to calculate the welfare loss from the obesity externality caused by health insurance. If the subsidy does not change the behavior of the people in a health insurance pool, then the subsidy is just a costless transfer from the thin to the obese that does not change social welfare. The key question is: to what extent do transfers to obese adults change incentives regarding their diet and exercise decisions? The welfare loss from the externality is proportional to both the size of the subsidy and the elasticity of body weight decisions with respect to the subsidy. We propose three tasks: (1) to measure the net subsidy from non-obese to obese individuals induced by Medicare from a lifetime point of view; (2) to measure the net subsidy induced by employer-provided health insurance; and (3) to measure the extent to which body weight decisions are distorted by health insurance induced subsidies.