Adverse Selection

Insurance companies use the term "adverse selection" to describe the tendency for only those who will benefit from insurance to buy it. Specifically when talking about health insurance, unhealthy people are more likely to purchase health insurance because they anticipate large medical bills. On the other side, people who consider themselves to be reasonably healthy may decide that medical insurance is an unnecessary expense; if they see the doctor once a year and it costs $250, that's much better than making monthly insurance payments of $400 (example figures).

The fundamental concept of insurance is that it balances costs across a large, random sample of individuals. For instance, an insurance company has a pool of 1000 randomly selected subscribers, each paying $100/month. One of them gets really sick while the others stay healthy, which means that the insurance company can use the money paid by the healthy people to treat the sick person. Adverse selection upsets this balance between healthy and sick subscribers. It will leave an insurance company with primarily sick subscribers and no way to balance out the cost of their medical expenses with a large number of healthy subscribers.

Because of adverse selection, insurance companies use a patient's medical history to screen out persons with pre-existing medical conditions. Before buying health insurance, a person typically fills out a comprehensive medical history form that asks whether the person smokes, how much the person weighs, whether the person has been treated for any of a long list of diseases and so on. In general, those who look like they will be large financial burdens are denied coverage or charged high premiums to compensate. On the other side, applicants can actually get discounts if they do not smoke and are healthy.

Starting in 1976, some states started providing "health insurance" "risk pools", which allow individuals who are medically-uninsurable through private health insurance to be able to purchase a state-sponsored health insurance plan, usually at higher cost. Minnesota was the first to offer such a plan, there are now 34 states which do. Plans vary greatly from state-to-state, both in the costs and benefits to consumers and to their methods of funding and operating. They serve a very small portion of the uninsurable market -- about 183,000 people in the USA[citation needed]-- but in best cases do allow people with pre-existing conditions such as cancer, diabetes, heart disease or other chronic illnesses to be able to switch jobs or seek self-employment without fear of being without health care benefits. Efforts to pass a national pool have as yet been unsuccessful, but some federal tax dollars have been awarded to states to innovate and improve their plans.