When people don't have health insurance through an employer or public plan, what do they do?

They don't buy health insurance in the individual market, for the most part.

That's the finding of a new report on individual health insurance purchasers by the Kaiser Family Foundation.

Essentially the researchers found that very few low-income people purchased individual policies. But it found pretty much the same at higher levels: 

"The evidence presented here suggests, however, that large numbers of even fairly well-off people remain uninsured rather than purchase non-group coverage when they are not offered coverage at work."

None of this may be surprising, but it has significant implications for healthcare reform

Most plans put forward by the candidates are based on the assumption that if coverage is more affordable, those who lack coverage will buy it.

Both Hillary Clinton's and Barack Obama's plans would make a set of private and public insurance options available via a newly created marketplace. Insurers could not deny coverage, or exclude those with pre-existing conditions.

With enough subsidies, perhaps, these measures could bring individual policies within reach of most of those who lack coverage through jobs or public plans. Clinton would mandate the uncovered buy insurance; Obama would not. 

John McCain's and Mike Huckabee's plans call for less insurance regulation, and for providing tax incentives to individuals to make coverage more affordable. The forces of the marketplace would hold down prices and improve coverage, they say, making it affordable to those who aren't covered. 

McCain would encourage groups and associations to offer insurance plans to members, creating a variety of additional group plan options.

The question, of course, is whether these measures will change the behavior of those who currently don't buy into the insurance system.

Is it just cost, or is it something else--fear of disclosing conditions to a new insurer, mutiple underwriting adventures to get a variety of quotes, the sheer complexity of comparing plans--that keeps people from buying in?

Or, in the end, will people be required--yes, mandated--to participated before they buy in?