Taxation,insurance, and precautionary labor

We examine optimal taxation and social insurance with adverse selection in competitive insurance markets. In a previous literature, it has been shown that, with perfect insurance markets, social insurance improves welfare since it is able to redistribute without creating distortions. This result has been taken as robust to the introduction of adverse selection as this would only provide additional justifications for social insurance. We show, however, that adverse selection can weaken the case for social insurance compared to a situation with perfect markets. Whenever social insurance mitigates private underinsurance, it also causes welfare-reducing effects by decreasing precautionary labor supply and hence tax revenue. In addition, adverse selection may reduce the redistributive potential of social insurance. We illustrate our general results using different equilibrium concepts for the insurance market. Notably, we derive conditions under which a complete renunciation of social insurance is optimal and the government only relies on income taxation to achieve its redistributive objectives.     

ESTIMATING WELFARE IN INSURANCE MARKETS USING VARIATION IN PRICES

We provide a graphical illustration of how standard consumer and producer theory can be used to quantify the welfare loss associated with inefficient pricing in insurance markets with selection. We then show how this welfare loss can be estimated empirically using identifying variation in the price of insurance. Such variation, together with quantity data, allows us to estimate the demand for insurance. The same variation, together with cost data, allows us to estimate how insurer's costs vary as market participants endogenously respond to price. The slope of this estimated cost curve provides a direct test for both the existence and nature of selection, and the combination of demand and cost curves can be used to estimate welfare. We illustrate our approach by applying it to data on employer-provided health insurance from one specific company. We detect adverse selection but estimate that the quantitative welfare implications associated with inefficient pricing in our particular application are small, in both absolute and relative terms.     

Minimum standards, insurance regulation and adverse selection: evidence from the Medigap market

This paper examines the implications of minimum standards for insurance markets. I study the imposition of binding minimum standards on the market for voluntary private health insurance for the elderly. The central estimates suggest that the introduction of the standards was associated with an 8 percentage point (25%) decrease in the proportion of the population with coverage in the affected market, with no evidence of substitution toward other, unregulated sources of insurance coverage. To explore possible factors contributing to the impact of the minimum standards, I develop comparative static predictions of the impact of imposing minimum standards in an insurance market with adverse selection. The observed changes in market equilibrium associated with the minimum standards are broadly consistent with these predictions, providing evidence of the existence of adverse selection in this insurance market. More importantly, they suggest that the presence of adverse selection—which in principle may provide an economic rationale for minimum standards—in practice may have exacerbated the declines in insurance coverage associated with the minimum standards.     

Adverse Selection in Health Insurance Markets: A Classroom Experiment

Adverse selection as it relates to health care policy will be a key economic issue in many upcoming elections. In this article, the author lays out a 30-minute classroom experiment designed for students to experience the kind of elevated prices and market collapse that can result from adverse selection in health insurance markets. The students should come away from the experiment understanding why adverse selection leads to high prices on good quality insurance and why it forces healthy individuals into low quality plans. Additionally, the experiment helps students think about the market characteristics that make health insurance particularly vulnerable to problems of asymmetric information. Finally, the experiment connects the adverse selection problem with key features of the 2010 Patient Protection and Affordable Care Act.     

Community rating and the market for private non-group health insurance

Prior research on adverse selection in health insurance markets has found only mixed evidence for adverse selection in group settings. We examine the impact of state community rating regulations enacted in the 1990s, which greatly limited insurers' ability to risk rate premiums, to determine if adverse selection is more evident in non-group insurance markets. Using data from large, national surveys we find evidence of a shift to a less healthy pool of non-group enrollees as a consequence of community rating. Community rating made healthy people 20 to 60% less likely to be insured by non-group health insurance; in addition, we found evidence that young and healthy people were 20 to 30% more likely to be uninsured as a result of community rating. We also find evidence that individuals in poor health were 35 to 50% more likely to be insured in the non-group market, but only limited evidence suggesting that persons in poor health were less likely to be uninsured. Our results are further supported by findings suggesting that non-group enrollees were sicker as a result of the community rating laws. Lastly, we find evidence suggesting that HMO penetration in the non-group market increased disproportionately in states that implemented community rating relative to states that did not.     

Asymmetric Information and Adverse Selection in Mauritian Slave Auctions

Information asymmetry is a necessary prerequisite for testing adverse selection. This paper applies this sequence of tests to Mauritian slave auctions. The theory of dynamic auctions with private and common values suggests that when an informed participant is known to be active, uninformed bidders will be more aggressive and the selling price will be higher. We conjecture that observable family links between buyer and seller entailed superior information and find a strong price premium when a related buyer purchased a slave, indicative of information asymmetry. We then test for adverse selection using sale motivation. Our results indicate large discounts on voluntary as compared to involuntary sales. Consistent with adverse selection, the market anticipated that predominantly low-productivity slaves would be brought to the market in voluntary sales.     

Adverse selection in annuity markets: Evidence from the British Life Annuity Act of 1808

We study adverse selection using data from an 1808 Act of British Parliament that effectively opened a market for life annuities. Our analysis indicates significant selection effects. The evidence for adverse selection is strongest for a sub-sample of annuitants whose annuities were purchased by profit-seeking speculators, a sub-sample in which “advantageous selection” resulting from multi-dimensional heterogeneity is unlikely to have been significant. These results support the view that adverse selection can be masked by advantageous selection in empirical studies of standard insurance markets.     

Does asymmetric information matter in the early insurance market? Evidence from the auto insurance market

In the late 1960s, the performance of automobile insurance declined dramatically in Japan in spite of rapid growth in the diffusion rate, and the premiums were sharply raised several times in order to improve the situation. This observation indicates the possible presence of adverse selection (death spiral), and provides an ideal situation for assessing informational asymmetry. Using bodily injury liability (BIL) insurance data from 46 Japanese prefectures over the period 1966 to 1975, this article tests two hypotheses of adverse selection: (i) high-risk drivers were more likely to join the BIL insurance market and (ii) sharp premium increases drove low-risk policyholders away. Various empirical analyses show that there is little evidence for either type of adverse selection. We also test whether a risk-misperception hypothesis can explain our results, and find some evidence that the population density have a significantly positive impact on the demand for BIL insurance.     

Private Information in Life Insurance,Annuity, and Health Insurance Markets

Economic theory predicts that private information on risks in insurance markets leads to adverse selection. To counterbalance private information, insurers collect and use information on applicants to assess their risk and to calculate premiums in an underwriting process. Using data from the English Longitudinal Study of Ageing (ELSA), this paper documents that differences in the information used in underwriting across life insurance, annuity, and health insurance markets attenuate private information to different extents. The results are in line with – and might help to reconcile – the mixed empirical evidence on adverse selection across these markets.     

中国居民医疗保险购买行为研究-基于商业健康保险的角度

本文通过健康保险市场供需双方行为分析,构建居民医疗保险购买行为模型,利用中国健康与营养调查数据(2000—2006),运用部分观测的二元Probit估计方法(Bivariate Probit with partial observability),从实证的角度分析商业健康保险市场中供需双方各自的风险选择行为,以及城乡地区居民对商业健康保险的潜在需求行为及其宏微观影响因素。本文发现:(1)城乡居民都存在显著的逆向选择行为;(2)城乡社会医疗保障对居民商业健康保险需求行为有显著的促进作用;(3)影响居民商业健康保险行为的其他因素还包括,个人的风险偏好和经济购买力。     

DOUBLE‐SIDED ADVERSE SELECTION IN THE PRODUCT MARKET AND THE ROLE OF THE INSURANCE MARKET*

I investigate the interrelation between a product market and an insurance market when adverse‐selection problems exist both in consumers and in firms. Firms offer warranties for product failures. Consumers may further purchase first‐party insurance for the residual risks of product failures. Given that the insurance market exists, two types of equilibria are possible: (a) Different firm types offer different pooling warranties attracting both good and bad consumer types or (b) good firms attract only bad consumers and bad firms attract both types of consumers. I discuss the existence and the efficiency implication of the insurance market.     

Information Revelation and Market Incompleteness

This paper introduces a theory of market incompleteness based on the information transmission role of prices and its adverse impact on the provision of insurance in financial markets. We analyse a simple security design model in which the number and payoff of securities are endogenous. Agents have rational expectations and differ in information, endowments, and attitudes toward risk. When markets are incomplete, equilibrium prices are typically partially revealing, while full relevation is attained with complete markets. The optimality of complete or incomplete markets depends on whether the adverse selection effect (the unwillingness of agents to trade risks when they are informationally disadvantaged) is stronger or weaker than the Hirshleifer effect (the impossibility of trading risks that have already been resolved), as new securities are issued and prices reveal more information. When the Hirshleifer effect dominates, an incomplete set of securities is preferred by all agents, and generates a higher volume of trade.     

The determinants of the demand for private health insurance under Medicare

Since the introduction of Medicare in 1984, the proportion of the Australian population with private health insurance has declined considerably. Insurance for health care consumption is compulsory for the public health sector but optional for the private health sector. In this paper, we explore a number of important issues in the demand for private health insurance in Australia. The socio-economic variables which influence demand are examined using a binary logit model. A number of simulations are performed to highlight the influence and relative importance of various characteristics such as age, income, health status and geographical location on demand. A number of important policy issues in the private health insurance market are highlighted. First, evidence is provided of adverse selection in the private health insurance pool, second, the notion of the wealthy uninsured is refuted, and finally it is confirmed that there are significant interstate differences in the demand for private health insurance.     

关于保险市场道德风险的微观经济学问题研究

保险市场是一个典型的信息不对称市场,主要表现为道德风险问题,这种对信息占有的不对称状况,很容易被保险市场参与者所利用,并导致保险市场运行的低效率。目前,中国保险市场上保险公司和投保人之间的道德风险问题表现得比较突出,已经成为制约保险业可持续发展的一个重要因素。本文从理论角度研究道德风险问题产生的机制,梳理信息不对称问题在理论上的解决方法,并从中得到保险市场应对道德风险问题的建议。     

外部干预与部分逆向选择--兼论地方保护与假冒伪劣顽症

本文基于Akedof逆向选择理论，通过引入外部干预因素修正，建立了一个能够在有限次交易中达到非零市场均衡的部分逆向选择模型，借以说明我国当前为什么存在规模化且“长生不衰”的劣质商品市场。在本文的模型中，虽然劣质商品市场会在一定程度上通过逆向选择规律的作用而自然萎缩，但由于“地方保护”等非市场因素的干扰，却不会萎缩至零。有时，劣质商品还甚嚣尘上，形成一定的规模。为了说明我们模型的内在合理性，本文以数量补贴影响预算约束为例，说明外部因素能够改变消费者无差异曲线，从而论证了将这种外部干预引入非封闭市场的合理性。     

生态视角的市场选择机制研究

从演化角度分析组织行为是目前经济学研究的热点。本文以生物进化为基础，探讨市场的构成和市场选择的内涵，提出了市场选择的机制包括效率甄别、互惠互利、产业选择、密度制约和产品对策影响，用动态分析的方法对市场理论进行了有益探索。     

Genetic adverse selection: Evidence from long-term care insurance and Huntington disease

Individual, personalized genetic information is increasingly available, leading to the possibility of greater adverse selection over time, particularly in individual-payer insurance markets. We use data on individuals at risk for Huntington disease (HD), a degenerative neurological disorder with significant effects on morbidity, to estimate adverse selection in long-term care insurance. We find strong evidence of adverse selection: individuals who carry the HD genetic mutation are up to 5 times as likely as the general population to own long-term care insurance. This finding is supported both by comparing individuals at risk for HD to those in the general population and by comparing across tested individuals in the HD-risk population with and without the HD mutation.     

Price signaling and the strategic benefits of price rigidities

We analyze trade between a perfectly informed price setting party (seller) and an imperfectly informed price taker (buyer). Differently from most of the literature, we focus on the case in which, under full information, it would be inefficient to trade goods of sufficiently poor quality. We show that the unique equilibrium surviving D1 is characterized by market breakdown, although trade would be mutually beneficial in some state of nature. This occurs independently of the precision of the information available to the buyer. The model thus implies that signaling through prices may exacerbate the effect of adverse selection rather than mitigate it. Under D1, the seller would always benefit from committing to prices that do not reveal her information. We develop this intuition by analyzing the strategic advantages of price rigidities. We show that price rigidities help restore trade and could even enhance effectiveness of prices as signals of quality.     

Is there dynamic adverse selection in the life insurance market?

This paper finds evidence of dynamic adverse selection in the life insurance market. Lower-risk individuals are more likely to cancel a policy, and to cancel one of greater face value conditional on cancelation, than are individuals with higher mortality risk.     

Health insurance market reform and employee compensation: The case of pure community rating in New York

Pure community rating, which was enacted to improve access to health insurance in New York's small group market in 1993, prevents carriers from charging different premiums based on the ages of a firm's workers. If small firms were adjusting compensation packages prior to reform to offset higher health care costs of older workers, then community rating could lead to greater relative wages for older workers post reform and not necessarily induce adverse selection that results in changes in who is insured. I present evidence showing that relative wages of older workers in small firms increased in comparison with other states and with large firms within New York following reform.