Commercial ACOs had lower expenses per Medicare enrollee and slightly higher overall quality-of-care scores. Larger, more mature commercial ACOs tend to have more processes in place to improve efficiency than their noncommercial counterparts do. Still, researchers note that few ACOs of any type have rigorous quality monitoring processes or substantial financial incentives tied to quality.
A report can be accessed at http://www.commonwealthfund.org/~/media/files/publications/in-the-literature/2016/oct/1907_peiris_acos_holding_commercial_contracts_ha_10_2016_itl_v2.pdf.