ACO indicates accountable care organization; MSSP, Medicare Shared Savings Program.
aACOs with more than 10 participating entities were statistically more likely to have achieved shared savings (P =.004).
This graph reflects the 58 MSSP ACOs with a 2012 or 2013 start date that generated savings and were eligible to receive a shared savings payment. An ACO participant is “an individual or group of ACO providers/suppliers that is identified by a Medicare-enrolled tax ID number, that alone or together with 1 or more other ACO participants composes the ACO, and that is included on the list of ACO participants required to be submitted as part of the MSSP application.”15 The number of participating entities was determined from publicly available information on each ACO’s website.