Health Care Spending and Utilization in Public and Private Medicare.

We compare healthcare spending in public and private Medicare using newly available claims data from Medicare Advantage (MA) insurers. MA insurer revenues are 30 percent higher than their healthcare spending. Adjusting for enrollee mix, healthcare spending per enrollee in MA is 9 to 30 percent lower than in traditional Medicare (TM), depending on the way we define "comparable" enrollees. Spending differences primarily reflect differences in healthcare utilization, with similar reductions for "high value" and "low value" care, rather than healthcare prices. We present evidence consistent with MA plans encouraging substitution to less expensive care and engaging in utilization management. (JEL H11, H42, H51, I11, I13).