This afternoon, Atul Gawande delivered this year’s commencement address at Harvard Medical School.

In his book “The Youngest Science,” the great physician-writer Lewis Thomas described his internship at Boston City Hospital in pre-penicillin 1937. Hospital work, he observed, was mainly custodial. “If being in a hospital bed made a difference,” he said, “it was mostly the difference produced by warmth, shelter, and food, and attentive, friendly care, and the matchless skill of the nurses in providing these things. Whether you survived or not depended on the natural history of the disease itself. Medicine made little or no difference.”

That didn’t stop the interns from being, as he put it, “frantically busy.” He learned to focus on diagnosis—insuring nothing was missed, especially an illness with an actual, effective treatment. There were only a few. Lobar pneumonia could be treated with antiserum, an injection of rabbit antibodies against the pneumococcus, if the intern identified the subtype correctly. Patients in diabetic coma responded dramatically to animal-extracted insulin and intravenous fluid. Acute heart failure patients could be saved by bleeding away a pint of blood from an arm vein, administering a leaf-preparation of digitalis, and delivering oxygen by tent. Early syphilitic paresis sometimes responded to a mix of mercury, bismuth, and arsenic. Surgery could treat certain tumors and infections. Beyond that, medical capabilities didn’t extend much further.

The distance medicine has travelled in the couple of generations since is almost unfathomable for us today. We now have treatments for nearly all of the tens of thousand of diagnoses and conditions that afflict human beings. We have more than six thousand drugs and four thousand medical and surgical procedures, and you, the clinicians graduating today, will be legally permitted to provide them. Such capabilities cannot guarantee everyone a long and healthy life, but they can make it possible for most.

People worldwide want and deserve the benefits of your capabilities. Many fear they will be denied them, however, whether because of cost, availability, or incompetence of caregivers. We are now witnessing a global societal struggle to assure universal delivery of our know-how. We in medicine, however, have been slow to grasp why this is such a struggle, or how the volume of discovery has changed our work and responsibilities.

The rapid growth in medicine’s capacities is not just a difference in degree but a difference in kind. We have experienced the sort of vast, quantum alteration that my father describes experiencing during a life that brought him from childhood in rural India to retirement from a surgical practice in Ohio. The greatest leap for him, he tells me, wasn’t in taking that first step off the plane in New York City, extraordinary as that was. It was in going from his rural farming village of five thousand people to Nagpur, a city of millions where he was admitted to medical school, three hundred kilometers away. Both communities were impoverished. But the structure of life, the values, and the ideas were so different as to be unrecognizable. Visiting back home, he found that one generation couldn’t even grasp the other’s challenges. Here is where we seem to find ourselves, as well.

We are at a cusp point in medical generations. The doctors of former generations lament what medicine has become. If they could start over, the surveys tell us, they wouldn’t choose the profession today. They recall a simpler past without insurance-company hassles, government regulations, malpractice litigation, not to mention nurses and doctors bearing tattoos and talking of wanting “balance” in their lives. These are not the cause of their unease, however. They are symptoms of a deeper condition—which is the reality that medicine’s complexity has exceeded our individual capabilities as doctors.

The core structure of medicine—how health care is organized and practiced—emerged in an era when doctors could hold all the key information patients needed in their heads and manage everything required themselves. One needed only an ethic of hard work, a prescription pad, a secretary, and a hospital willing to serve as one’s workshop, loaning a bed and nurses for a patient’s convalescence, maybe an operating room with a few basic tools. We were craftsmen. We could set the fracture, spin the blood, plate the cultures, administer the antiserum. The nature of the knowledge lent itself to prizing autonomy, independence, and self-sufficiency among our highest values, and to designing medicine accordingly. But you can’t hold all the information in your head any longer, and you can’t master all the skills. No one person can work up a patient’s back pain, run the immunoassay, do the physical therapy, protocol the MRI, and direct the treatment of the unexpected cancer found growing in the spine. I don’t even know what it means to “protocol” the MRI.

Before Elias Zerhouni became director of the National Institutes of Health, he was a senior hospital leader at Johns Hopkins, and he calculated how many clinical staff were involved in the care of their typical hospital patient—how many doctors, nurses, and so on. In 1970, he found, it was 2.5 full-time equivalents. By the end of the nineteen-nineties, it was more than fifteen. The number must be even larger today. Everyone has just a piece of patient care. We’re all specialists now—even primary-care doctors. A structure that prioritizes the independence of all those specialists will have enormous difficulty achieving great care.

We don’t have to look far for evidence. Two million patients pick up infections in American hospitals, most because someone didn’t follow basic antiseptic precautions. Forty per cent of coronary-disease patients and sixty per cent of asthma patients receive incomplete or inappropriate care. And half of major surgical complications are avoidable with existing knowledge. It’s like no one’s in charge—because no one is. The public’s experience is that we have amazing clinicians and technologies but little consistent sense that they come together to provide an actual system of care, from start to finish, for people. We train, hire, and pay doctors to be cowboys. But it’s pit crews people need.

Another sign this is the case is the unsustainable growth in the cost of health care. Medical performance tends to follow a bell curve, with a wide gap between the best and the worst results for a given condition, depending on where people go for care. The costs follow a bell curve, as well, varying for similar patients by thirty to fifty per cent. But the interesting thing is: the curves do not match. The places that get the best results are not the most expensive places. Indeed, many are among the least expensive. This means there is hope—for if the best results required the highest costs, then rationing care would be the only choice. Instead, however, we can look to the top performers—the positive deviants—to understand how to provide what society most needs: better care at lower cost. And the pattern seems to be that the places that function most like a system are most successful.

By a system I mean that the diverse people actually work together to direct their specialized capabilities toward common goals for patients. They are coordinated by design. They are pit crews. To function this way, however, you must cultivate certain skills which are uncommon in practice and not often taught.