Separate and unequal: self-segregation in health insurance.
Separate and unequal: self-segregation in health insurance.
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隔离与不平等：健康保险中的自我隔离。
DOI：
10.1097/mlr.0b013e31818863b3
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发表时间：
2008
期刊：
影响因子：
3
通讯作者：
R. Evans
中科院分区：
文献类型：
--
作者：
R. Evans
这一期由Naessens等人撰写的《医疗保健》专刊中的一篇文章对健康经济学家特别感兴趣，因为它在几乎“实验室”的条件下，证实了30多年前的重要理论结果。保险范围的选择(其他条件相同)导致人们自我选择进入更多和更少的高风险群体。因此，更多的选择会给那些风险更高的人、老年人和慢性病患者带来更大的经济负担。这一理论是有效的，并与当今的卫生政策直接相关。1970年，阿克洛夫·S的经典著作《柠檬》一文探讨了信息不对称下的市场动态。在极端情况下，交易所一方的交易者可能拥有关于特定产品相关特征的完整信息(二手车卖家、个人健康保险合同的买家)，而另一方的交易者可能只知道提供出售的二手车的平均特征，或潜在保险购买者的平均风险状况。然后，高质量汽车的卖家将被提供给他们的汽车太低的价格；低风险买家将被收取过高的保险费用。如果最高质量的二手车和风险最低的购车者做出回应，退出市场，这将降低待售汽车的平均质量，并提高那些拥有医疗保险的人的平均风险。根据相对数量和风险，这可能会引发连锁反应，导致更多更高质量的汽车和更低风险的人离开。市场可能会陷入“死亡螺旋”，完全消失。然而，罗斯柴尔德和斯蒂格利茨3证明，即使健康保险合同的卖家不知道个别购买者的风险状况，他们也可以通过提供不同保费和覆盖水平的多个合同来诱使(理性的、完全知情的、自利的和风险厌恶的)买家透露自己的状况。他们的示范模式包括高风险和低风险买家。如果提供两种不同的合同，低风险买家将选择较低的保费和较不全面的覆盖范围，更多的潜在用户费用，而高风险人群将为更全面的覆盖支付更多费用。就像他们在梅奥做的那样。在Naessens等人的现实世界中，分离当然不是完全的。但风险较高的员工显然是在自我选择进入更高收益、更高保费的人群，反过来，这一理论也是有效的。(阿克洛夫和斯蒂格利茨与迈克尔·斯宾塞分享了2001年诺贝尔经济学奖，以表彰他们在不完全信息经济学方面的研究。)然而，确实应该强调的是，相对于单一溢价合同，这一分离过程具有显著的分配效果。收入从较少的参保人群转移到较健康的人群，有两种不同的方式。(如果保费和使用费的增加允许降低雇主的供款，也有从雇员转移到雇主的情况。)。低风险买家受益，因为他们的保费不再需要支付高风险人群的部分费用。而后者相应地为他们购买的任何保险支付更高的费用。但除此之外，因为自我选择的动机是增加用户对
article in this Special Theme Issue of Medical Care by Naessens et al1 is of particular interest to a health economist, because it provides a confirmation, under almost "laboratory" conditions, of important theoretical results from more than 30 years ago. Choice of insurance coverage (all else equal) leads people to self-select into more and less high-risk groups. Greater choice thus has the effect of placing a greater financial burden on those at higher risk the elderly and the chronically ill. The theory works, and has immediate relevance to present-day health policy. In 1970, Akerlof s classic "Lemons" paper2 explored the dynamics of markets with asymmetric information. In the extreme case, transactors on one side of an exchange might have complete information about the relevant characteristics of a given product (sellers of used cars, buyers of individual health insurance contracts) whereas those on the other side might know only the average characteristics of used cars offered for sale, or the average risk status of would-be insurance purchasers. Sellers of higher quality cars would then be offered too low a price for their cars; low risk buyers would be overcharged for their coverage. If the highest quality used cars and the lowest risk buyers should respond by leaving the market, this would lower the average quality of cars for sale and raise the average risk of those with health insurance. Depending upon the relative numbers and risks, this could set off a chain reaction such that more higher quality cars and lower risk people leave. The market could go into a "death spiral" and completely disappear. Rothschild and Stiglitz,3 however, demonstrated that even when sellers of health insurance contracts do not know the risk status of individual purchasers, they could induce (rational, fully-informed, self-interested, and risk-averse) buyers to reveal their status by offering multiple contracts with differing premiums and levels of coverage. Their demonstration model includes high-risk and low-risk buyers. If 2 different contracts are offered, low-risk buyers will choose the lower premiums and less comprehensive coverage more potential user charges while high-risk people will pay more for more comprehensive coverage. As they did at Mayo. In the real world of Naessens et al, the separation is of course not complete. But the higher-risk employees are clearly self-selecting into the higherbenefit, higher-premium pool, and conversely the theory works. (Akerlof and Stiglitz shared the 2001 Nobel Prize in Economics with Michael Spence for their work on the economics of imperfect information.) It should be noted, indeed emphasized, however, that this separation process has significant distributional effects relative to the single premium contract. Income is transferred from the less to the more healthy members of the insured population, in 2 distinct ways. (There is also a transfer from employees to the employer, insofar as the increases in premiums and user charges permit lowering the employer's contribution.) Low-risk buyers gain because their premiums no longer have to cover part of the costs of high-risk people. And the latter correspondingly pay more for whatever coverage they buy. But in addition, because self-selection is motivated by increased user charges on