Medicare Star Ratings are a quality scoring system that grades Medicare Advantage and Medicare Part D prescription drug plans on a scale of 1 to 5 stars, with 5 being the highest. The Centers for Medicare & Medicaid Services (CMS) publishes these ratings each year to help you compare plans based on quality of care, not just cost and benefits.
How the 1-to-5 Scale Works
Each plan receives an overall star rating based on its performance across dozens of individual measures. For each measure, CMS sets performance thresholds called “cut points” that determine whether a plan earns 1, 2, 3, 4, or 5 stars on that measure. Those individual scores are then combined into one overall rating. In plain terms: 1 star means poor performance, 3 stars is average, and 5 stars is excellent.
Plans that consistently earn low ratings get flagged with a “low performing” icon on the Medicare Plan Finder. For 2026, four Medicare Advantage prescription drug contracts carry that warning label. On the other end, 21 contracts earned perfect 5-star ratings and are highlighted as top performers.
What the Ratings Actually Measure
The ratings pull from several data sources that capture different aspects of your experience with a plan. The two biggest inputs are clinical quality data and member satisfaction surveys.
Clinical performance comes largely from HEDIS (Healthcare Effectiveness Data and Information Set), which tracks things like whether members with diabetes are getting their blood sugar checked on schedule, how often preventive screenings happen, and how well chronic conditions are being managed. This data is gathered from medical charts, insurance claims for office visits and hospitalizations, and member surveys.
Member experience comes from CAHPS (Consumer Assessment of Healthcare Providers and Systems) surveys, which are mailed to a random sample of Medicare beneficiaries with telephone follow-ups. These surveys ask about your experience getting appointments, how well your doctors communicate, whether you had trouble getting prescriptions filled, and how easy it is to reach customer service.
Other measures factor in things like how accurately the plan processes claims, how often members file complaints or leave the plan, and how well the plan helps members manage medications safely.
Why Star Ratings Matter to Your Plan
Star ratings aren’t just informational. They have real financial consequences for insurance companies, which is why plans work hard to improve them. Plans that earn 4 or more stars receive quality bonus payments from CMS, worth roughly 5% of the plan’s benchmark payment. That extra money often flows back to members in the form of lower premiums, reduced copays, or additional benefits like dental and vision coverage.
This creates a direct link between a plan’s star rating and the value you get as a member. A 4.5-star plan may offer richer benefits than a 3-star plan in the same area, not because it charges more, but because it receives bonus funding for its quality performance.
How Most Plans Perform
For 2025, the average star rating for Medicare Advantage prescription drug plans is 3.92, weighted by enrollment. About 40% of these contracts earned 4 stars or higher. But because larger plans tend to perform better, roughly 62% of all MA-PD enrollees are in a plan rated 4 stars or above. If you’re in Medicare Advantage with drug coverage, there’s a better-than-even chance your plan already meets that quality threshold.
Stand-alone Part D prescription drug plans tell a different story. Their average rating is 3.06, and only about 27% of contracts hit the 4-star mark. Weighted by enrollment, just 5% of stand-alone drug plan members are in a 4-star-or-better plan. If you’re in Original Medicare with a separate Part D plan, it’s worth checking your plan’s rating more carefully.
The 5-Star Special Enrollment Perk
One of the most practical reasons to pay attention to star ratings is the special enrollment period available for 5-star plans. Normally, you can only switch Medicare Advantage or Part D plans during the annual Open Enrollment Period in the fall. But if a plan with a perfect 5-star overall rating is available in your area, you can switch to it almost any time of year.
This 5-star Special Enrollment Period runs from December 8 through November 30 of the following year, and you can use it once during that window. It applies to Medicare Advantage Plans, Medicare Cost Plans, and Medicare drug plans. You don’t need any other qualifying event to use it. The only requirement is that a 5-star plan serves your area and you haven’t already used this enrollment period that year.
How to Check a Plan’s Rating
CMS publishes star ratings on the Medicare Plan Finder at Medicare.gov. When you enter your zip code and browse available plans, each one displays its overall star rating alongside cost and coverage details. You can also see individual measure scores if you want to dig into where a plan excels or falls short.
Ratings are updated every fall, typically in October, for the following plan year. So the ratings published in October 2024 apply to plans you’d enroll in for 2025 coverage. Keep in mind that a plan’s rating reflects past performance, usually based on data from one to three years prior. A plan that recently improved its operations may not see that reflected in its stars right away, and a plan that recently cut corners may still carry a high rating for a year or two.
When comparing plans, star ratings work best as one factor alongside premiums, out-of-pocket costs, provider networks, and drug formularies. A 4.5-star plan with a narrow network that excludes your doctor isn’t necessarily better for you than a 3.5-star plan where your providers are all in-network. But when two plans look similar on paper, the one with the higher star rating is generally delivering a better experience to its members.