http://www.truthout.org/docs_2005/111405M.shtml-snip-
To understand adverse selection, imagine what would happen if there were only one health insurance company, and everyone was required to buy the same insurance policy. In that case, the insurance company could charge a price reflecting the medical costs of the average American, plus a small extra charge for administrative expenses.
But in the real insurance market, a company that offered such a policy to anyone who wanted it would lose money hand over fist. Healthy people, who don't expect to face high medical bills, would go elsewhere, or go without insurance. Meanwhile, those who bought the policy would be a self-selected group of people likely to have high medical costs. And if the company responded to this selection bias by charging a higher price for insurance, it would drive away even more healthy people.
That's why insurance companies don't offer a standard health insurance policy, available to anyone willing to buy it. Instead, they devote a lot of effort and money to screening applicants, selling insurance only to those considered unlikely to have high costs, while rejecting those with pre-existing conditions or other indicators of high future expenses.
This screening process is the main reason private health insurers spend a much higher share of their revenue on administrative costs than do government insurance programs like Medicare, which doesn't try to screen anyone out. That is,
private insurance companies spend large sums not on providing medical care, but on denying insurance to those who need it most. What happens to those denied coverage? Citizens of advanced countries - the United States included - don't believe that their fellow citizens should be denied essential health care because they can't afford it. And this belief in social justice gets translated into action, however imperfectly. Some of those unable to get private health insurance are covered by Medicaid. Others receive "uncompensated" treatment, which ends up being paid for either by the government or by higher medical bills for the insured. So
we have a huge private health care bureaucracy whose main purpose is, in effect, to pass the buck to taxpayers.-snip-
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