The Centers for Medicare and Medicaid Services uses a star rating system to evaluate Medicare Advantage plans and Medicare Part D plans. Plans can receive from one star (poor) to five stars (excellent), and the ratings are based on numerous measures, including factors such as customer service, how easy it is for enrollees to receive care, how well the plan does at improving or maintaining members’ physical and mental health, and how quickly the plan handles appeals – among many others. (See Tables 9, 10, and 11).