(ACO) regulations - American Society of Anesthesiologists

CMS-1345-P 267
beneficiaries. In response to our November 17, 2010 RFI, many commenters recognized
the prevalence of solo and small practices and the importance of these providers for rural
areas and for the treatment of specific patient populations, for example, individuals with
mental health and substance abuse disorders or beneficiaries residing in skill nursing
facilities. Many of these commenters urged us to consider policies and models that
encourage the participation of solo and small practices and to address barriers they face in
forming ACOs such as access to up-front capital to invest in the infrastructure and
resources required to redesign care. One option that would help accomplish this would
be to vary the confidence intervals used to establish MSRs so that smaller practices
would have relatively lower MSRs. Conversely, in recognition that they are likely to be
already established, possess prior experience, and thus better able to achieve savings,
larger ACOs would have their MSRs based on a higher confidence interval, resulting in a
relatively higher MSR.
The MSRs are estimated to provide confidence that an ACO with a given number
of beneficiaries and assumed to be of average national baseline per-capita expenditure
and expenditure growth rate would be unlikely to achieve a shared savings payment by
random chance alone. A specific MSR is a function of both the number of assigned
beneficiaries and a chosen confidence interval. Recognizing the higher uncertainty
regarding expenditures for smaller ACOs and the desire to encourage participation by
smaller ACOs, for the one-sided model, we propose to set the confidence interval to 90
percent for ACOs of 5,000 beneficiaries, resulting in an MSR of 3.9 percent. For ACOs
with 20,000 and 50,000 beneficiaries, we propose to set the confidence interval to 95
percent and 99 percent, respectively, resulting in MSRs of 2.5 percent and 2.2 percent.