This week on Conversations on Health Care®, Mark Masselli and Margaret Flinter speak with Dr. John Wennberg whose research for the past 40 years has focused on variations in health care around the country and its implications on the individual, the community and the health care system as a whole. Dr. Wennberg is the Peggy Y. Thomson Professor for the Evaluative Clinical Sciences at Dartmouth and founder and director of the Dartmouth Institute for Health Policy and Clinical Practice, home to the Dartmouth Atlas Project.