Medicare Advantage (Part C) plans from carriers such as UnitedHealthcare, Humana, Aetna, Kaiser Permanente, and many Blues receive annual star ratings from the Centers for Medicare & Medicaid Services (CMS). Ratings run from 1 to 5 stars (with half-stars in some displays) and summarize quality and performance measures for that contract—not a guarantee that your next specialist visit will go smoothly. Use stars as one screen beside premium, MOOP, network, and drug costs on Medicare.gov Plan Finder.
Original Medicare plus Medigap is a different stack: What is Medigap. Medigap guaranteed-issue windows are separate from Advantage star shopping: Guaranteed-issue Medigap basics.
What star ratings usually reflect
CMS aggregates dozens of measures that can include (categories evolve by year—confirm current Medicare.gov methodology):
| Theme (illustrative) | Examples of what CMS looks at |
|---|---|
| Staying healthy / screening | Preventive care, flu shots, monitoring for chronic conditions |
| Managing chronic conditions | Diabetes, blood pressure, and related care process measures |
| Member experience | Surveys about getting appointments, care coordination, customer service |
| Complaints / retention | Complaint rates, members leaving the plan, appeals outcomes |
| Customer service / drug plan ops | Call-center and Part D operational measures when the contract includes drugs |
A 5-star contract scored well on the weighted mix CMS used for that year. A 2-star or 2.5-star plan raised quality flags—worth reading the measure detail, not only the headline. Low-performing contracts can face enrollment limits or other CMS actions in severe cases; always check the current year’s label on Plan Finder.
Part D drug stages are scored partly inside stars for MA-PDs but still need their own cost model: Medicare Part D donut hole basics.
How to use stars without over-trusting them
- Filter, don’t crown. Start with doctors, hospitals, and pharmacies you need in-network; then compare stars among plans that actually fit.
- Read premium + MOOP + drug package together. A 4.5-star plan with a sky-high MOOP or weak formulary can still cost more in a bad year (MOOP basics).
- Check the year. Stars lag real-world changes; a new network cut may not yet show in last year’s measures.
- Separate Medigap shopping. Stars are an Advantage / Part D tool—not a Medigap letter grade (What is Medigap).
- Use SHIP help. State Health Insurance Assistance Programs can walk Plan Finder without a sales script.
EOB literacy after you enroll still matters: Medical bills and insurance. Deductible vocabulary on non-Medicare plans: Health insurance deductibles.
Worked example: comparing three MA-PD cards
Alex is 67 in a metro county and needs an in-network cardiologist at a major hospital system. Plan Finder (illustrative, not quotes) shows:
| Plan | Stars | Monthly premium | In-network MOOP | Estimated annual drug cost (Alex’s list) |
|---|---|---|---|---|
| Humana-style HMO A | 4.5 | $28 | $4,200 | $1,100 |
| UnitedHealthcare-style PPO B | 3.5 | $0 | $6,700 | $1,450 |
| Regional Blues-style HMO C | 5.0 | $72 | $3,900 | $980 |
Alex’s cardiologist is out of network on HMO C despite the 5.0 stars—so C drops. Between A and B, Alex prefers A’s lower MOOP and better drug estimate even though B’s premium is $0, because a hospital year could erase B’s “savings.” Stars helped Alex avoid a low-rated outlier earlier in the filter, but network fit decided the short list.
What stars do not fix
- A narrow network that excludes your oncologist
- Prior-auth denials on a drug your specialist prefers
- Confusing MOOP vs Part D cost-sharing
- Assuming last year’s 5 stars equals this year’s service after a contract change
- Replacing advice from Medicare.gov, your plan’s Evidence of Coverage, or SHIP
Checklist
- Open Medicare.gov Plan Finder for your ZIP and enter doctors, drugs, and pharmacies.
- Note each plan’s star rating and the measurement year shown.
- Compare premium, MOOP, and estimated drug cost—not stars alone.
- Confirm specialists and hospitals are in-network for that specific contract ID.
- Re-check ratings and networks every Annual Enrollment Period.
- Call SHIP if two plans look close and you want a non-sales walkthrough.
Educational only. Not insurance, tax, or legal advice. Not a plan recommendation. CMS star-rating measures and cut points change by year; confirm with Medicare.gov, your plan’s Evidence of Coverage, and your state SHIP program.