Guide · Medicare Advantage quality
Understanding Medicare Advantage star ratings
What the CMS 1–5 star scale actually measures, how it is calculated, and why it is the most reliable way to compare plan quality.
The short answer
CMS star ratings are a government-verified quality score, not a marketing claim, a 4.5 or 5-star plan has demonstrably better preventive care, chronic-disease management, and member satisfaction than lower-rated plans.
- 1–5★
- overall quality scale, in half-stars
- 40+
- quality measures behind each rating
- Yearly
- ratings refresh every fall
- 5★
- unlocks year-round enrollment
Star ratings measure quality, not price. Use them first, then compare cost on Medicare.gov.
Every year, the Centers for Medicare & Medicaid Services (CMS) evaluates every Medicare Advantage plan and assigns it an overall quality rating from 1 to 5 stars. This rating system is one of the most reliable tools beneficiaries have for comparing plan quality, but many people don't know how it works or what it actually measures.
What the Star Scale Means
Star ratings run from 1 to 5, in half-star increments:
- 5 stars: Excellent. Top tier. Plans can also accept new members year-round (Special Enrollment Period).
- 4–4.5 stars: Above average. Generally strong quality performance.
- 3–3.5 stars: Average. Meeting basic standards but not leading in quality.
- 2–2.5 stars: Below average. CMS may take corrective action.
- 1–1.5 stars: Poor performance. Plans may face sanctions or termination.
The 10 Quality Domains
CMS measures plan quality across 10 domains (5 for health plans and 5 for drug plans in combo plans):
Health Plan Domains
- HD1, Staying Healthy (Screenings, Tests, Vaccines): How often members get recommended preventive care like flu shots, colorectal cancer screenings, and breast cancer screenings.
- HD2, Managing Chronic (Long Term) Conditions: How well the plan helps members with diabetes, heart disease, and other chronic conditions manage their health.
- HD3, Member Experience with the Health Plan: Survey results measuring how satisfied members are with their plan's services, communication, and care.
- HD4, Member Complaints and Changes in Performance: Whether members file complaints and whether plan performance is improving or declining.
- HD5, Health Plan Customer Service: How responsive the plan is to calls and appeals, and whether decisions are made correctly.
Drug Plan Domains (if plan includes Part D)
- DD1, Drug Plan Customer Service
- DD2, Member Complaints and Changes in Drug Plan Performance
- DD3, Member Experience with the Drug Plan
- DD4, Drug Safety and Accuracy of Drug Pricing
How the Overall Star Rating Is Calculated
CMS calculates an overall star rating as a weighted average of individual measure scores. Some measures (like medication safety and member experience surveys) carry more weight than others.
The overall star rating is separate from individual domain scores. A plan can score highly in one domain and average in another, the overall rating reflects the full picture.
Worked Example: How a 3.8 Plan Becomes 4.5 Stars
CMS weights measures differently. A plan scoring 3.0 on member complaints but 5.0 on medication adherence can still earn 4.5 overall because medication safety measures are triple-weighted. Here is a simplified example with five weighted measures:
| Measure | Score (1-5) | Weight | Weighted Score |
|---|---|---|---|
| Breast cancer screening | 4 | 1.0 | 4.0 |
| Diabetes blood sugar controlled | 5 | 3.0 | 15.0 |
| Member complaints | 3 | 2.0 | 6.0 |
| Customer service call wait time | 4 | 1.0 | 4.0 |
| Drug safety (high-risk meds) | 5 | 3.0 | 15.0 |
Total weighted score = 44.0 / 10.0 total weight = 4.4. CMS rounds to nearest half-star, so this plan earns 4.5 stars. Note that the two triple-weighted measures (diabetes control and drug safety) contributed 30 of the 44 points, 68% of the final score from just 2 of 5 measures.
Understanding Guardrails and Cut Points
CMS uses statistical guardrails to set the star thresholds each year. Rather than fixed percentage targets, cut points are based on the distribution of all plans' performance. This means a measure score of 85% could earn 5 stars one year and only 4 stars the next, if other plans improved and the distribution shifted. CMS applies a 5% guardrail so that thresholds cannot shift more than 5 percentage points in a single year, preventing dramatic swings but still rewarding relative improvement.
What Changed in the 2026 Star Rating Methodology
CMS updates the star rating methodology annually. Key changes for 2026 include:
- Tukey outlier deletion: Extreme high and low measure scores are excluded before setting cut points, reducing distortion from outlier plans.
- Cohort adjustment: Newer plans (less than 3 years of data) are rated against a separate cohort rather than being compared to mature plans.
- Reward factor: Plans with consistent high performance (4+ stars for 3 consecutive years) receive a 0.1 to 0.4 reward factor bonus added to their summary score.
Why Star Ratings Matter Financially
Star ratings aren't just for beneficiaries, they have direct financial consequences for insurers:
- Quality Bonus Payments: Plans rated 4+ stars receive additional CMS payments (bonuses) that can be used to reduce premiums, lower copays, or add benefits.
- Special Enrollment: 5-star plans can accept new enrollees at any time during the year, not just during Open Enrollment.
- Low Performer Flags: Plans with 3 or fewer stars for 3+ consecutive years get flagged with a "low performing" designation visible to beneficiaries.
Quality Bonus Payment Dollar Impact
CMS quality bonus payments are substantial. A 4-star plan receives roughly a 5% bonus on its county benchmark payment; a 5-star plan receives approximately 10%. To see the scale, take an illustrative plan whose benchmark is about $800 per member per month (benchmarks vary widely by county): the bonus works out to roughly an extra $40 per member per month at 4 stars, or $80 at 5 stars. Across 50,000 members, a 5-star bonus at that rate would be on the order of $48 million a year, which is why plans invest heavily in quality-improvement programs. Actual benchmarks, bonus rates, and rebate rules are set by CMS and differ by plan and county.
What the Low Performing Icon Means for Your Coverage
Plans flagged with the Low Performing Plan (LPP) icon have scored below 3.0 stars for 3 or more consecutive years. CMS publishes these ratings prominently on Medicare.gov Plan Finder. While LPP plans are not automatically terminated, they face heightened CMS oversight and must submit corrective action plans. For beneficiaries, the LPP icon is a strong signal to consider switching, especially since there are often 4+ star alternatives available in the same county.
Where to Find Star Ratings
You can look up star ratings for plans in your county on PlainMedicare: browse by state, then select your county to see all available plans with their current star ratings. You can also see top-rated plans nationally.
CMS also publishes star ratings on Medicare.gov Plan Finder and in the annual Medicare & You handbook.
Limitations of Star Ratings
Star ratings are valuable but not the only factor to consider:
- A highly-rated plan is only useful if your doctors are in its network
- Ratings are based on prior year performance, quality can change
- New plans have no rating until they complete their first full year
- Star ratings don't measure every aspect of plan quality (e.g., prior authorization burdens)
Sources
- CMS. 2026 Medicare Advantage and Part D Star Ratings Technical Notes. cms.gov
- Medicare.gov. How are plans rated?
- CMS Star Ratings Data: Example: Devoted Health 5-star plan
Putting star ratings to work
Use the rating to shortlist, then confirm the details that the score can't see.
- Start from 4★+ plans in your county, they have proven quality across CMS measures. Top-rated plans
- Confirm your doctors and pharmacies are in-network before enrolling, a great rating can’t fix a missing provider. Choosing a plan
- Check this year’s rating, not last year’s, a 5-star plan can slip, and a rising plan can be a smart pick. Browse by state
Star ratings measure quality, not price, and reflect prior-year performance. Always verify current ratings and costs on Medicare.gov before you enroll.
Frequently Asked Questions
How often are Medicare Advantage star ratings updated?
CMS releases updated star ratings annually, typically in October. The new ratings apply to the following plan year. For example, the 2026 star ratings were released in fall 2025 and apply to plans during the 2026 plan year.
Do all Medicare Advantage plans receive a star rating?
Not necessarily. New plans and plans with insufficient data may receive a 'Too New to Rate' designation. Plans need at least one full year of data to receive an official CMS star rating.
Can a 5-star plan lose its rating?
Yes. Star ratings change every year based on updated performance data. A plan rated 5 stars one year could drop to 4 or 4.5 the next if quality measures decline. Always check the current year's rating.
What is a Low Performing Plan (LPP) icon?
CMS marks plans that have received below 3 stars for 3 or more consecutive years with a Low Performing Plan icon. These plans are flagged to help beneficiaries make more informed choices.
Does a higher star rating mean lower cost?
Not directly. Star ratings measure quality, not price. However, 4- and 5-star plans receive CMS quality bonus payments that plans can use to offer lower premiums or richer benefits, so there is often an indirect relationship.