In 1967, Jack Wennberg, a young medical researcher at Johns Hopkins, moved his family to a farmhouse in northern Vermont.
Dr. Wennberg had been chosen to run a new center based at the University of Vermont that would examine medical care in the state. With a colleague, he traveled around Vermont, visiting its 16 hospitals and collecting data on how often they did various procedures.
The results turned out to be quite odd. Vermont has one of the most homogenous populations in the country -- overwhelmingly white (especially in 1967), with relatively similar levels of poverty and education statewide. Yet medical practice across the state varied enormously, for all kinds of care. In Middlebury, for instance, only 7 percent of children had their tonsils removed. In Morrisville, 70 percent did.