Despite initial concerns that hospitals would dominate the formation of accountable care organizations, the first survey of public and private ACOs found the majority of the organizations are physician-led. The results of the National Survey of Accountable Care Organizations, conducted by researchers at the Dartmouth Institute for Health Policy & Clinical Practice, were published in the June edition of the health policy journal Health Affairs. The survey's findings suggest that moving the health-care delivery system away from fee-for-service won't be accomplished without strong, effective leadership from physicians.