The villain never seems to change. Whenever talk turns to the high costs of health care, fingers are pointed at hospital emergency rooms and their misuse by patients--mostly poor and uninsured--who come to the ER with their health woes. They may have a cough that, thanks to a lack of access to primary care, has worsened into pneumonia or a cut that's developed into a systemic infection. Those ER visits turn what should have been a $70 office charge into a $700 emergency room tab. And then the hospital, the state and insurance companies end up footing the bill. Meanwhile, hospitals in many cities have had to close their doors to ambulances for several hours each day because of overcrowding of their emergency facilities.

The ER scenario is accepted wisdom in health care circles and so bounded in logic that health reform policies are based on it. When Maine put its Dirigo health plan in place three years ago, a fiscal tenet of the program was savings that would ensue from insuring the uninsured and keeping them out of the emergency room. Similarly, Illinois' All Kids program--an attempt at universal health insurance for children--is slated to save the health care system money by giving low-income families access to physician offices and clinics, thus tamping down their huge emergency room bills.

In some states--particularly along the country's southern border-- emergency room crowding is seeping into the immigration debate. Those who want a hard line taken against illegal immigrants say their use of free services in emergency rooms is pushing out others and increasing the cost of care for everyone.

Clearly, the use of ERs by poor, non-paying patients is a genuine health issue that needs to be addressed. But now a recent study of who's who among patients in emergency rooms by the Center for Studying Health System Change has found that the perceived wisdom about who's misusing care in the ER is wrong.

Researchers looked at patient traffic in emergency rooms in 60 communities all around the country and found that ER use was relatively low in communities with higher numbers of uninsured, Hispanics or non-citizens. Instead, use was high in places with more elderly residents and patients who have to wait a long time for appointments with their own doctors, and places where a smaller percentage of the population is enrolled in HMOs. "Emergency room use is up across the population," says Peter J. Cunningham, the report's author, "including more middle-class folks with private insurance."

According to the study, the average use of emergency rooms is 32 visits per 100 residents. But Orange County, California, with its substantial numbers of both uninsured residents and immigrants, had the lowest ER usage rate at 21 visits per 100. The same held true for Phoenix and Miami-Dade--low usage but high uninsured and immigrant rates. By contrast, Cleveland, with low numbers of uninsured and relatively low levels of immigrant residents, had a high of 40 visits per 100 residents. Ditto for Boston.

As for Medicaid patients, they were not a factor in overuse of emergency rooms when they had access to HMOs. With managed care--at least managed care that works well--patients are part of a system that provides preventive care and regular access to care.

So it turns out that those at the lower end of the income charts are not the ones clogging up emergency departments. Instead, the report found, it's a very different population--older, middle class and unable to gain access to care when they need it. While these patients and their insurance companies pay the bill for ER visits, that's still money being spent on an expensive--and often unnecessary--form of care. And this, in turn, affects health insurance premiums and the cost of health coverage to employers (which includes, of course, states and localities)--an issue that is becoming politically toxic.

Addressing the financial drain and overcrowding that defines the emergency room dilemma includes the problems of the uninsured poor-- they often appear in the ER when their health is so compromised that they require more extensive and expensive treatment that they can't afford to pay for. Their needs can't be underestimated. But a solution must also include the issue of access problems at the higher end of the scale. Overcrowding in emergency rooms is becoming a crisis-- visits increased by 26 percent between 1993 and 2003 and have been climbing since then--but the dilemma is, notes Cunningham, "a manifestation of a much more systemic problem."