Moral Hazard

Moral hazard is the prospect that a party insulated from risk may behave differently from the way it would behave if it were fully exposed to the risk. In insurance, moral hazard that occurs without conscious or malicious action is called morale hazard.

Moral hazard is related to information asymmetry, a situation in which one party in a transaction has more information than another. The party that is insulated from risk generally has more information about its actions and intentions than the party paying for the negative consequences of the risk. More broadly, moral hazard occurs when the party with more information about its actions or intentions has a tendency or incentive to behave inappropriately from the perspective of the party with less information.

Moral hazard arises because an individual or institution does not take the full consequences and responsibilities of its doings, and therefore has a tendency to act less carefully than it alternately would, leaving another party to hold some responsibility for the consequences of those actions. For example, a person with insurance against automobile theft may be less cautious about locking his or her car, because the negative consequences of vehicle theft are (partially) the responsibility of the insurance company.

Moral hazard also arises in a principal-agent problem, where one party, called an agent, acts on behalf of another party, called the principal. The agent usually has more information about his or her actions or intentions than the principal does, because the principal usually cannot completely monitor the agent. The agent may have an incentive to act inappropriately (from the viewpoint of the principal) if the interests of the agent and the principal are not aligned.

　　道德风险并不等同于道德败坏。道德风险是80年代西方经济学家提出的一个经济哲学范畴的概念，即“从事经济活动的人在最大限度地增进自身效用的同时做出不利于他人的行动。” 或者说是：当签约一方不完全承担风险后果时所采取的自身效用最大化的自私行为。道德风险亦称道德危机。

　　在经济活动中，道德风险问题相当普遍。获2001年度诺贝尔经济学奖的斯蒂格里茨在研究保险市场时，发现了一个经典的例子：美国一所大学学生自行车被盗比率约为10%，有几个有经营头脑的学生发起了一个对自行车的保险，保费为保险标的15%。按常理，这几个有经营头脑的学生应获得5%左右的利润。但该保险运作一段时间后，这几个学生发现自行车被盗比率迅速提高到15%以上。何以如此？这是因为自行车投保后学生们对自行车安全防范措施明显减少。在这个例子中，投保的学生由于不完全承担自行车被盗的风险后果，因而采取了对自行车安全防范的不作为行为。而这种不作为的行为，就是道德风险。可以说，只要市场经济存在，道德风险就不可避免。

    当某人获得某保险公司的保险，由于此时某人行为的成本由那个保险公司部分或全部承担。此时保险公司面临着道德风险。如果此人违约造成了损失，他自己并不承担全部责任，而保险公司往往需要承担大部分后果。此时某人缺少不违约的激励，所以只能靠他的道德自律。他随时可以改变行为造成保险公司的损失，而保险公司要承担损失的风险。

    在医疗保险领域，道德风险往往引起医疗费用快速不合理增长。道德风险产生的根源是信息不对称,表现形式包括被保险人的过度消费和医疗机构的诱导需求。