Magic bullets come and go in the world of health policy, but the accountable care organization (ACO) is likely to be a durable reform. Except for group practices like Geisinger, Harvard Vanguard, Kaiser Permanente, systems like the VA, and local communities in which independent practitioners have established cooperative collaborations, health care has been grotesquely uncoordinated in the U.S. ACOs speak to that structural lesion.

Title III of the Patient Protection and Affordable Care Act puts ACOs forward as an innovation to promote the quality and efficiency of health care. “Efficiency” isn’t controversial. Doing a second MRI because the results from the first one aren’t available is pure waste. But not doing an MRI when a plain film, or a careful physical examination and history, could be “adequate,” is more complex. Some would call that “efficiency” or “evidence based practice.” Others would call it “rationing.” But there’s no uncertainty about how to label not offering an effective, and desired, service – that’s definitely rationing.

In the October 6 issue of JAMA, Dr. Robert Brook of RAND has an important brief article: “What if Physicians Actually Had to Control Medical Costs?” As a thought experiment, Brook imagines that enough money is available for a physician to treat 100 patients with condition A or condition B. Treating each patient costs $1000, and only $100,000 is available. Epidemiological data predicts that the physician will see 100 patients with A and 100 patients with B. The benefit of treating A is four times the benefit of treating B. What should the physician do?

Brook believes, and I agree, that even when we have wrung all efficiency savings out of health care, there will still be beneficial interventions physicians want to provide, and patients want to receive, that our society will not be prepared to pay for. He argues, and I agree, that the medical profession is unprepared for engaging with this eventuality:

Policy makers discuss controlling medical costs, and academics publish articles analyzing cost-control approaches. But physicians seem oblivious to the possibility that, sooner or later, care will need to be explicitly rationed. Physicians who actually order the health-related diagnostics or treatment for which taxpayers pay must decide how they will cope with explicit rationing. Will there be a physician plan or health professional plan to deal with the eventuality of explicit rationing? Should planning begin now instead of waiting until the decision is imminent?

There’s no way that the need for rationing could have been part of the federal health reform process. We’re not yet mature enough as a body politic to deal with that piece of reality without going ballistic about “death panels.” But wishful thinking and political immaturity don’t change the fact that rationing happens now, will have to be acknowledged in the future, and is an ethical requirement, not an abomination. Brook concludes, and I again agree:

…an explicit plan for rationing needs to be developed. But who will do it, and how?

Physicians (and other health professionals), patients and the wider public should be the “who?” And with regard to “how?,” the experience of the Didcot practice in the U.K. provides a model of deliberative process. With help from two ethicists, the general practice group created guidelines for the practice, reviewed them with members of the practice, and made them public.

No one wants to go first in discussing rationing. To do so would invite savage, know-nothing political attack. But it’s important for public deliberation about how to ration in a clinically guided, ethically justifiable and potentially socially acceptable manner to get underway. Accountable Care Organizations are an ideal setting for physicians and patients to join together in this kind of what if scenario planning.

Jim Sabin is a psychiatrist and director, ethics program, Harvard Pilgrim Health Care.  He blogs at Health Care Organizational Ethics.