Last January, in a column on the nation’s new health care law[1], I wrote that medical insurance “coverage seems to be important.” Those tepid words upset Hagerstown resident and health care professional Brooks McBurney, who wrote in a subsequent letter to the editor, “Lack of medical coverage for 30 million to 50 million people would seem to warrant a higher qualifier than ‘seems.’ … We pay far more for medical care than any other advanced country, and for this we get poor results.”[2]

McBurney appears to be stating an obvious truth: If people have medical coverage—whether through insurance or a government program—then they’d be more likely to seek care when they need it and would live longer, healthier lives, right?

The problem is, social science has had a hard time finding a statistical link between coverage and improved physical health.[3] Just last month, in an announcement that made national headlines, researchers conceded that the latest attempt to show such a link has yielded disappointing results. The announcement raises difficult questions for the new health care law’s supporters.

The research effort, known as the Oregon Health Insurance Experiment, resulted from that state’s 2008 decision to expand its Medicaid coverage for low-income, non-elderly adults. When Oregon received far more applicants than it could finance, the state used a series of lotteries to select who could enroll. That gave researchers an opportunity to study the benefits of medical coverage: they followed the health and financial condition of lottery entrants and looked for differences between the winners and losers.

To the researchers’ surprise, after two years there appears to be little difference between the two groups’ physical health.[4] Lottery winners did receive more care, were diagnosed with more illnesses, and consumed more medication, but there was no statistical difference between the groups’ blood pressure, cholesterol level, or blood sugar level—health measures the researchers expected would respond to medical coverage over the two-year period. Likewise, there was no statistical difference between the groups’ self-reported feeling of physical well-being, experience of pain or sense of happiness.

How can that be? The explanation may lie in an oft-overlooked fact: people without medical coverage still receive medical care. In fact, since 1996 the typical uninsured person below age 65 (the Medicare-eligible age) received only 30 percent less care (measured in dollars) than the typical under-65 person with public coverage like Medicaid or Medicare.[5] (It should be noted that the typical person with private coverage received twice as much care as the uninsured person.) Couple that fact with the common belief among health care experts that at least a third of the money spent on medical care yields no benefit, and the Oregon results begin to make sense. If the uninsured make more efficient use of their health care dollars (and research suggests they do[6]), then it shouldn’t be surprising that their physical health is little different from people with Medicaid.

With that said, the Oregon experiment did show some important benefits from coverage. Lottery winners were significantly less likely to experience depression. They also were far less likely to be burdened with heavy medical debt. Better mental health and lower debt are good things—though it’s unclear whether those gains justify all the taxes, fees, fines, mandates, complexities and unintended consequences of the new health care law.

Returning to McBurney’s criticism of my claim that “coverage seems to be important,” I do want to amend what I wrote. A more accurate statement would have been that people who expect the new law will yield a physically healthier America seem to be destined for disappointment.

Thomas A. Firey is a senior fellow at the Maryland Public Policy Institute and a Washington County native.