Although CMS wants to push more providers into risk-bearing accountable care organizations, Brookings Institution scholars and many providers say the agency could inadvertently do the opposite by making it possible for providers in ACOs that don't accept the risk of penalties to get much larger bonuses than providers in risk-bearing ACOs. The current Medicare ACO framework allows larger bonuses for risk-bearing ACOs, but when CMS incorporates ACOs into the new physician pay system, bonus-only ACOs might actually be able to...