Medicare Star Ratings

The Medicare star rating system assesses the quality of Medicare Advantage and Medicare Part D prescription drug plans based on several categories and topics, including customer service and access to preventive care. You can use these ratings to find high-quality private Medicare plans in your area.

What Is the Medicare Star Rating System?

Many establishments, such as hotels and restaurants, use 5-star rating systems to promote high-quality service. Medicare is no different.

The Medicare star rating program is an objective way for consumers to compare private Medicare Advantage plans and Medicare Part D prescription drug plans based on quality and performance.

Each plan receives a rating between 1 and 5 stars, with 1 being poor and 5 being excellent.

Medicare quality star ratings are assigned at the contract level instead of for each individual plan. Most contracts cover multiple plans.

Medicare updates these ratings each fall for the following year.

Did You Know?
In 2021, 80 percent of Medicare Advantage beneficiaries are enrolled in plans with quality ratings of 4 or more stars.

Medicare Advantage and Part D prescription drug plans are administered by private insurance companies that contract with the federal government.

Each private plan must meet certain standards, but coverage and cost can vary widely from plan to plan.

The U.S. Centers for Medicare & Medicaid Services implemented the star rating system in 2008 to help potential enrollees compare plans available in their area while encouraging plan providers to step up and improve quality.

High-performing plans receive extra money from the federal government, further incentivizing companies to improve service and expand offerings.

The Affordable Care Act (ACA) created financial bonus payments for Medicare Advantage and Part D plans that receive at least 4 stars. These bonuses can provide a 5 to 10 percent increase in funding.

Private plans without star ratings (due to low enrollment or being too new) also receive bonus payments, but at a lower rate of 3.5 percent.

Private companies are encouraged to use these bonuses to reduce out-of-pocket costs for beneficiaries and offer additional supplemental benefits.

Between 2015 and 2021, total annual bonuses to Medicare Advantage plans increased dramatically from $3 billion to $11.6 billion, according to the Kaiser Family Foundation.

What Does It Measure?

Medicare Advantage plans and Part D plans are measured differently within the star rating system.

Medicare Advantage plans are across 33 topics in five categories while Part D prescription plans are measured on 14 topics in four categories.

Medicare Advantage plans with prescription drug coverage are measured across 47 topics in nine categories.

Categories Used to Measure Medicare Star Ratings
Staying Healthy
How accessible are preventative services that keep members healthy, like flu shots and screenings?
Member Complaints and Performance
How often do members file complaints or face issues getting services?
Member Experience
How easy is it for members to get the care they need, fill prescriptions and see specialists?
Customer Service
How efficient are call center services? How quickly does the plan provider process appeals and new enrollments?
Managing Chronic Conditions
How effectively do plans coordinate care? How often do members receive services related to long-term health conditions?

Certain measures within each category are weighted differently. For example, the highest weighted group includes improvement measures, such as how much the contract’s overall star rating improved or declined from the previous year.

Medicare uses administrative data, contractor data and information from member satisfaction surveys to assess performance and assign star ratings.

What Is the 5-Star Special Enrollment Period?

If a Medicare Advantage or Part D plan with a 5-star rating is available in your area, you can use the 5-star special enrollment period to switch from your current Medicare plan to one with a 5-star rating.

You can use this special enrollment period one time between December 8 and November 30.

You can use this special enrollment period to switch to a:
  • 5-Star Medicare Advantage-only plan
  • 5-star Medicare Advantage plan with prescription drug coverage
  • 5-star Medicare Part D prescription drug plan
  • 5-star Medicare cost plan

If you are currently enrolled in a 5-star plan, you can also switch to a different 5-star plan during this special enrollment period.

Once you sign up for a new plan, your benefits will begin the first day of the month following the month the plan received your enrollment request.

Last Modified: August 5, 2021

5 Cited Research Articles

  1. Fuglesten Biniek, J., Freed, M., Damico, A., et al. (2021, June 21). Medicare Advantage in 2021: Star Ratings and Bonuses. Retrieved from
  2. Shah, S. and Sun, E. (2021, February 4). Rating The Medicare Advantage Star Ratings—Improving The Status Quo. Retrieved from
  3. Centers for Medicare & Medicaid Services. (2019, October 1). Medicare 2020 Part C & D Star Ratings Technical Notes. Retrieved from
  4. Iowa SHIP. (n.d.). 5-Star Enrollment Period. Retrieved from
  5. (n.d.). 5-star special enrollment period. Retrieved from