Even with the advent of ACOs, for the foreseeable future the MA program is likely to remain numerically the most important alternative to TM. Although MA currently enrolls nearly a third of Medicare beneficiaries, potential reimbursement reductions could diminish the array of supplemental benefits offered to MA beneficiaries, increase premium and cost sharing levels, and decrease the willingness of both beneficiaries and plans to participate. Moreover, many of these changes could also affect selection, the management of care, and the prices private MA plans negotiate with health care providers with repercussions for the entire delivery system. Given the prominence of MA in the Medicare program, evaluating these critical aspects of MA in light of these policy changes represents an important opportunity for research.
This project continues our study of the provision of services, selection, and the quality of care under MA and how all of those change over time as new policies are implemented. By continuing the complementary stock and flow comparisons of health risks in the MA and TM populations that we have employed using both administrative and survey data, as well as margin data from MA plans, we will clarify how payment changes affect risk selection and whether selection patterns become more socially efficient. Through the incorporation of data from Truven MarketScan as well as from several additional health plans that serve this market, we will be able to examine for the first time pricing MA plans obtain from providers and how those prices change over time and relate to market-level factors such as provider concentration. We also will extend our work comparing the provision of services and quality of care both over time and to additional clinical areas, including comparisons of drug treatment patterns for chronic diseases. In short, in our current project we have developed methods to address the salient policy issues that MA poses, we have addressed them at a time when reimbursement was becoming more generous and MA was expanding, and now we can apply our methods to a more austere reimbursement policy in which some successful ACO plans may nonetheless decide to convert to MA plans.