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，并测量了相关的健康和会计成本。十多年前，沃尔夫和科尔迪茨估计，每年因肥胖造成的医疗成本和工作效率下降超过680亿美元。与肥胖相关的发病率和会计成本使得经济学家和公共卫生从业人员都提倡积极的公共干预。然而，肥胖导致的医疗费用的衡量标准本身与公众控制肥胖的行动是否合理的争论无关。更确切地说，最相关的是体重决定的成本，而不是由成年人做出这些决定所承担的成本（以下称为外部成本）。肥胖得到（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。本文献仅关注肥胖和非肥胖成人的医疗支出差异，而忽略了相关的支付差异。以医疗保险为例，本文献没有考虑税收、肥胖相关死亡率差异和医疗支出时间的差异贡献。在雇主提供私人保险的情况下，文献忽略了一种可能性（由补偿工资差异理论暗示），即相对于较瘦的工人，覆盖的肥胖工人减少了，因为他们的预期医疗支出更高。即使对补贴进行适当的衡量，也不足以计算健康保险造成的肥胖外部性带来的福利损失。如果补贴没有改变健康保险池中人们的行为，那么补贴只是一种从瘦到胖的无成本转移，不会改变社会福利。关键问题是：转移到肥胖成年人身上会在多大程度上改变他们的饮食和运动决策动机？外部性造成的福利损失与补贴的规模和相对于补贴的体重决策弹性成正比。我们提出了三个任务：(1)从终身角度衡量医疗保险诱导的非肥胖者对肥胖者的净补贴；(2)衡量雇主提供的医疗保险带来的净补贴；(3)衡量健康保险补贴对体重决策的扭曲程度。

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.