Medicare's private plans: a report card on Medicare Advantage.

With higher payments and expanded private-plan authority, Medicare Advantage (MA) has caused the market to grow. One in three Medicare beneficiaries with Part D now gets this coverage through MA. Analysis of the sources of and reasons for enrollment growth suggest a troubling report card. Clearly, the Medicare Modernization Act (MMA) has expanded choice and the private-sector role. But it also has added to Medicare's complexity and costs and has created potential inequities, without apparent improvements in quality. However the debate ends, a stronger system of performance monitoring and accountability is needed to meet Medicare's essential fiduciary requirements and oversight responsibilities.