VOX CLAMANTIS:

His name is John E. Wennberg, M.D., M.P.H; but at Dartmouth, we all call him Jack. He is the reason Dartmouth is on the health policy map.

Jack went on to document similarly wildly variable medical practices in the other New England states. But it wasn't until he compared two of the nation's most prominent medical communities -- Boston and New Haven, Conn. -- that the major medical journals took notice. In the late 1980s, both the Lancet and the New England Journal of Medicine published the findings that Boston residents were hospitalized 60% more often than their counterparts in New Haven. Oh, by the way, the rate of death -- and the age of death -- in the two cities were the same.

It was an alternative version of the Harvard-Yale game -- and Yale won.

In the 1990s, Jack led the effort to catalog the patterns of medical care for the entire nation, and the Dartmouth Atlas of Health Care was born. The atlas data were central to the contention, made by the Obama administration, that there was substantial waste in U.S. medical care.

You probably knew that already. And Jack's work is a big part of the reason you do.

OK, it's interesting history. But how is it relevant today?

Because this work represents the genesis of a new science -- medical care epidemiology, a science we are about to need a lot more of.

Classically, epidemiology examines exposures relevant to infectious disease: think water supplies as the source of cholera epidemics in the mid-1800s to food supplies as the source of recent Salmonella outbreaks. In the mid-1900s, epidemiology began to tackle exposures relevant to chronic disease -- discovering, for example, how cigarette smoking increases the risk of dying from lung cancer 20 times.

Medical care epidemiology examines the effect of exposure to medical care: how differential exposure across time and place relates to population health outcomes. It acknowledges that medical care can produce both benefits and harms, and that conventional concerns about underservice should be balanced by concerns about overdiagnosis and overtreatment. Think of it as surveillance for a different type of outbreak: outbreaks of diagnosis and treatment.

Medical care epidemiology is not a substitute for traditional clinical research. Instead, it is a complement, because there are many questions that cannot be studied in randomized trials. How do new diagnostic and treatment technologies affect clinical practice? Do specialists better spend their time doing procedures or providing support for primary-care practitioners? How frequently should patients be seen? Do patients do better taking more medicines or fewer?

Jack is the father of this new science and the inspiration that led the next generation of physicians to enter the field. His colleagues will honor his contribution this month at Dartmouth on this 40th anniversary of his Science paper.

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