Shopping for a Medicare Advantage or Part D plan can feel overwhelming; there are dozens of options, each with different premiums, networks, drug formularies, and benefits. Medicare star ratings exist to help cut through that noise. They give you a standardized measure of how well a plan actually performs, not just what it promises on paper.
This guide explains exactly how the Medicare star rating system works, what goes into a plan's rating, how to use ratings when comparing plans, and what to look for when you're ready to enroll.
What Are Medicare Star Ratings?
Medicare star ratings are a quality scoring system created and maintained by the Centers for Medicare & Medicaid Services (CMS). Every year, CMS evaluates Medicare Advantage (Part C)plans and standalone Part D prescription drug plans on a scale of 1 to 5 stars, where 5 stars represents the highest level of quality and performance.
The ratings are published annually on Medicare.gov's Plan Finder tool, giving beneficiaries a consistent, objective way to compare plans beyond just cost and coverage. Think of them as a report card for Medicare plans: one that measures not just what a plan covers, but how well it delivers on that coverage in practice.
Star ratings are assigned at the contract level, meaning the rating applies to all plans under a given insurer's Medicare contract in a region, rather than to individual plan variations.
Why Does Medicare Use A 5-Star Rating System?
Medicare uses a 5-star scale because it provides enough range to meaningfully differentiate between poor, average, and high-performing plans without becoming so granular that the distinctions lose practical meaning for the average beneficiary.
The 5-star framework also creates a clear action threshold:
- Plans rated below 3 stars for three or more consecutive years can face consequences from CMS, including potential termination from the Medicare program.
- On the other end of the scale, plans that consistently earn a 5-star rating unlock a special enrollment benefit (more on that below).
Beyond simplifying plan comparisons, the 5-star system is also tied to Medicare’s Quality Bonus Payment program. Medicare Advantage plans that achieve 4 stars or higher may receive additional payments from CMS. These payments may allow plans to offer enhanced benefits or maintain competitive premiums. However, the specific benefits and costs vary by plan, so it’s important for beneficiaries to review plan details when making decisions.
How Are Medicare Star Ratings Calculated?
CMS evaluates Medicare Advantage and Part D plans across dozens of individual quality measures, which are grouped into broader categories. The measures draw from multiple data sources (including claims data, health outcomes surveys, and member satisfaction surveys) to build a comprehensive picture of plan performance.
For Medicare Advantage (Part C) plans, the key measurement categories include:
- Staying healthy (screenings, tests, and vaccines). This category measures how well plans support preventive care, including breast cancer screenings, flu shots, blood pressure screenings, and other recommended preventive services. Plans that help members stay ahead of health issues score higher here.
- Managing chronic conditions. This measures how effectively plans help members with ongoing health conditions (including diabetes, high blood pressure, and rheumatoid arthritis) manage their care. Metrics include medication adherence, appropriate follow-up care, and health outcomes over time.
- Member experience. CMS surveys plan members directly about their experiences with their plan, including how easy it is to get care, how well their doctors communicate, and how satisfied they are overall. This is one of the most heavily weighted categories in the star rating calculation.
- Customer service. This category evaluates the plan's administrative performance, including call center responsiveness, the accuracy of plan information, and how efficiently the plan handles appeals and grievances.
- Care coordination and patient safety. This measures how well plans coordinate care across providers, track readmission rates, and promote safe medication practices.
For standalone Part D prescription drug plans, CMS evaluates measures specific to drug coverage, including medication adherence for common chronic conditions, drug safety, and the member experience around pharmacy access and customer service.
Each individual measure is scored and weighted, and CMS combines them into a single overall star rating for the plan. CMS also applies a health equity adjustment that can impact ratings for plans serving higher proportions of dual-eligible beneficiaries or those with social risk factors; an acknowledgment that some plans operate in more challenging environments than others.
Ratings are updated every fall, with new scores released ahead of the Annual Enrollment Period so beneficiaries have current information when comparing plans.
What Is A Good Medicare Star Rating?
Plans that receive 4 stars or higher are generally viewed as high-performing based on these standardized measures. Here's a practical breakdown of what each rating level means:
| Stars | What It Means |
| ⭐⭐⭐⭐⭐ (5 stars) | Excellent; among the highest-performing plans available |
| ⭐⭐⭐⭐ (4 stars) | Above average; strong performance across most measures |
| ⭐⭐⭐ (3 stars) | Average; meets basic standards but has room for improvement |
| ⭐⭐ (2 stars) | Below average; has underperformed on key quality measures |
| ⭐ (1 star) | Poor; significant performance concerns; at risk of CMS action |
Most Medicare Advantage plans fall in the 3 to 4 star range. Fewer than 10% of plans typically achieve a 5-star rating in any given year, making a 5-star plan a meaningful distinction.
That said, star ratings are one important input, but not the only one. A 4-star plan that includes your doctors, covers your medications, and fits your budget may be a better choice for you personally than a 5-star plan that doesn't.
This is exactly the kind of nuance that Healthpilot's Plan Fit score is designed to capture, layering your personal health information on top of objective quality data to surface the plans that actually fit your life.
How Do Star Ratings Affect Your Enrollment Options?
Star ratings are for more than comparing plans side-by-side; they can also affect when you're allowed to make changes to your coverage.
The 5-Star Special Enrollment Period is one of Medicare's lesser-known enrollment windows. If a 5-star Medicare Advantage or Part D plan is available in your area, you can switch to it once between December 8th through November 30th of the following year outside of the standard Annual Enrollment Period. This gives high-performing plans a unique advantage: beneficiaries can move to them at almost any point during the year.
Generally, plan changes can only be made during designated Medicare enrollment periods unless you qualify for a Special Election Period due to specific qualifying life events.
- Initial Enrollment Period (IEP): The 7-month window around your 65th birthday when you first become eligible for Medicare
- Annual Enrollment Period (AEP): October 15th-December 7th each year, when anyone with Medicare can switch plans
- Medicare Advantage Open Enrollment Period (MA OEP): January 1st-March 31st, when individuals already enrolled in a Medicare Advantage plan can make a one-time change, such as moving to another Medicare Advantage plan or returning to Original Medicare (with the option to add a Part D plan).
How To Use Star Ratings When Comparing Plans
Star ratings are most useful when you treat them as a filter rather than a final answer. Here's a practical approach:
- Start with eligibility. Use a Medicare plan comparison tool like Healthpilot to see which Medicare Advantage and Part D plans are available in your ZIP code. Not all plans are available in all areas.
- Filter by star rating. Many consumers focus their comparison on plans rated 3.5 stars or higher. This narrows your options to plans with a reasonable track record of quality without eliminating too many choices.
- Compare costs and coverage. Within your shortlist of higher-rated plans, compare monthly premiums, out-of-pocket maximums, drug formularies, and provider networks. A high star rating means little if the plan doesn't cover your medications or include your doctors.
- Read the member experience scores. Within the overall star rating, CMS breaks out individual measure scores. Member experience and customer service measures are particularly worth reviewing, as they reflect what it's actually like to use the plan day-to-day, not just whether it covers the right services on paper.
- Check year-over-year trends. A plan that has improved its star rating over consecutive years is often a better bet than one whose rating has declined, even if the current scores are similar.
Healthpilot does much of this work for you automatically. When you enter your doctors, medications, and ZIP code, our platform compares every available plan (factoring in star ratings alongside cost, coverage, and network fit) and surfaces your best options with a personalized Plan Fit score. You will also see star ratings clearly displayed next to each plan option.