Accountable care organization musical chairs: will there be a seat remaining for the small group or solo practice? [corrected].

When it was introduced in the Affordable Care Act of 2010 as the new 2012 payment model for Medicare, an accountable care organization (ACO) was a new and untested concept in healthcare delivery and payment. The authors estimated the likelihood of engagement in ACOs by small group and solo healthcare practitioners. An evaluation of five case studies showed that significant organizational, financial, and technological challenges had to be met in order to launch an ACO. Sufficient resources to meet those challenges were best supplied by large organizations. Small or solo practices participated only through varying levels of integration as salaried physicians or in independent practice associations or physician hospital organizations.