Reps. Diane Black (R-TN) and Peter Welch (D-VT) are pushing legislation to test capitated Medicare ACOs in a demonstration that eventually could be ramped up nationally. The pay structure of the ACOs would resemble HMOs (health maintenance organizations), but patients would be allowed to visit providers out of network as they are in ACOs. The idea of the bipartisan House bill, introduced last week, is to move ACOs away from fee-for-service by paying them a set amount for each enrolled...