Medicare Star Ratings Explained: How to Use Them When Choosing a Plan for Your Parent

When you're comparing Medicare Advantage or Part D plans for your parent, the Medicare star rating system is one of the few objective, government-calculated data points you can use. It's not perfect — and it doesn't replace comparing premiums, networks, and drug formularies — but understanding what the stars mean and how to use them will help you avoid the worst plans and spot the better ones.

What Are Medicare Star Ratings?

CMS (the Centers for Medicare and Medicaid Services) rates Medicare Advantage and Part D prescription drug plans on a scale of 1 to 5 stars every year. One star is the lowest quality; five stars is the highest.

These ratings measure how well the plan performs on dozens of quality and performance metrics — things like how often members get recommended preventive screenings, how well the plan manages chronic conditions, how easy it is for members to get care, and how the plan handles member complaints.

The ratings are published each fall ahead of the Annual Open Enrollment Period (October 15 through December 7), so you can look them up before helping your parent choose or change a plan.

How CMS Calculates the Stars

For Medicare Advantage plans that include drug coverage (MA-PD plans, which is most of them), CMS evaluates performance across five broad categories:

1. Staying Healthy: Screenings, Tests, and Vaccines Did members get their annual flu shots, colorectal cancer screenings, mammograms, and other preventive services? Plans that actively help members stay on top of preventive care score higher here.

2. Managing Chronic (Long-Term) Conditions How well does the plan support members with ongoing conditions like diabetes, heart disease, or hypertension? Metrics include things like whether diabetic members are getting A1C tests and whether blood pressure is being controlled.

3. Plan Responsiveness and Care This covers member experience: how often members get needed care without delays, how easy it is to get specialist referrals, and how well the plan's member services team performs.

4. Member Complaints and Changes in the Plan's Performance CMS tracks how many formal complaints were filed against the plan, whether the plan is improving or declining over time, and audit results. A plan that has worsening scores year-over-year is penalized here.

5. Drug Plan Quality (for prescription drug coverage) For the Part D portion of an MA-PD plan, CMS tracks whether members are getting appropriate medications for their conditions, whether they're staying on maintenance drugs, and how the plan handles medication safety for older adults.

For standalone Part D plans (used alongside Original Medicare and a Medigap policy), the ratings focus on the drug-specific categories: pricing accuracy, formulary management, medication safety, and customer service.

What the Star Thresholds Actually Mean

Here's how to interpret the ratings in practice:

5 Stars: The plan performs exceptionally well across all categories. There are very few 5-star plans nationally, and they're not available in every county.

4–4.5 Stars: High-quality plans. These are the realistic target when searching for a plan. A 4-star or higher rating indicates the plan consistently performs above average on quality metrics and has a reasonably low complaint rate.

3–3.5 Stars: Adequate, but the plan has real weaknesses. These plans aren't necessarily dangerous, but they have meaningful gaps in quality on at least some metrics. Don't choose a 3-star plan when a 4-star plan is available in your parent's area for a comparable premium.

2.5 Stars or Below: CMS considers these underperforming plans. Plans that receive 2.5 stars or below for three consecutive years can lose their contract with CMS. If your parent is currently enrolled in a 2.5-star or lower plan, switching should be a priority during the next enrollment window.

The practical rule: Look for a plan rated 4 stars or higher. Use 3.5 stars as the floor you're willing to accept if there's a specific reason (price, network access, or drug formulary) that makes the plan otherwise the best fit.

The 5-Star Special Enrollment Period

One practical benefit of the star rating system: if a 5-star plan is available in your parent's area, they can switch to it at any time during the year — not just during October open enrollment. This is called the 5-Star Special Enrollment Period.

This matters if your parent is currently in a low-quality plan and realizes the problem mid-year. They can switch to a 5-star plan once per year without waiting. Check medicare.gov/plan-compare to see whether a 5-star plan is offered in their ZIP code.

Why Star Ratings Have Limits

Star ratings are useful, but they don't tell the whole story. Here's what the ratings don't capture:

Network strength. A plan can score 4 stars on quality metrics and still have a narrow network that excludes your parent's preferred specialists or the regional hospital they trust. Always verify that specific doctors are in-network before enrolling.

Formulary coverage. A highly rated plan may not cover your parent's specific medications — or may cover them at a tier that makes them unaffordable. Run every medication through the Medicare Plan Finder (medicare.gov/plan-compare) to see actual drug costs before deciding.

Local vs. national performance. Ratings are calculated at the plan contract level, not at the local market level. A plan may score 4 stars nationally but have poorer service in your parent's specific county or region.

Annual changes. A plan that earned 4.5 stars this year may have earned 3.5 stars last year. Look at the trend if you can — a plan consistently at 4+ stars is more reliable than one that bounced up from 2.5 recently.

How to Look Up Star Ratings

The easiest way is at medicare.gov/plan-compare:

1. Enter your parent's ZIP code.
2. Choose the plan type (Medicare Advantage or Drug Plan).
3. Each plan card shows its star rating prominently.
4. You can filter results by minimum star rating to eliminate low-quality plans from the comparison immediately.

You can also call 1-800-MEDICARE and ask a representative to tell you the star rating for a specific plan.

Star Ratings and the Bigger Picture

Medicare star ratings are one input among several when choosing a plan for your parent. Use them as a first filter — eliminate anything below 3.5 stars unless there's a compelling reason — and then dig into the details that star ratings don't cover: premiums, drug costs, network, prior authorization requirements, and the plan's maximum out-of-pocket limit.

For Medicare Advantage specifically, remember that the maximum out-of-pocket limit in 2026 can reach $9,350 for combined in-network and out-of-network services. Even a 5-star plan can expose your parent to significant costs in a serious illness year. That's why star ratings alone are never enough — they measure quality, not cost.

Getting Medicare Plan Help Without Sales Pressure

Insurance brokers and agents often emphasize specific plans based on their commission structure rather than objective quality. SHIP (State Health Insurance Assistance Program) counselors at shiphelp.org provide free, unbiased help comparing plans — they're not paid commissions and have no incentive to steer your parent toward any particular plan.

For families who want to do the analysis themselves, our Medicare Enrollment Guide covers how to evaluate Medicare Advantage plans, compare star ratings with drug costs and network access, and make a final choice that fits your parent's health profile and budget. It's designed for adult children managing this process step by step.