Institutional Affiliation: Harvard Medical School
|Spending Reductions in the Medicare Shared Savings Program: Selection or Savings?|
with J. Michael McWilliams, Bruce E. Landon, Michael E. Chernew: w26403
Evidence of patient and physician turnover in accountable care organizations (ACOs) has raised concerns that ACOs may be earning shared-savings bonuses by selecting for lower-risk patients or providers with lower-risk panels. We conducted three sets of analyses to examine risk selection in the Medicare Shared Savings Program. First, we estimated overall MSSP savings through 2015 using a difference-in-differences approach and methods that eliminated selection bias from ACO program exit or changes in the practices or physicians included in ACO contracts. We then checked for residual risk selection at the patient level. Second, we re-estimated savings with methods that address undetected risk selection but could introduce bias from other sources. These included patient fixed effects, baselin...