Medicare Star Ratings

Key facts

Published by

CMS, in Medicare Plan Finder, before the annual enrollment period

Scale

1 to 5 stars, in half-star increments

Regulations

42 CFR 422.160 to 422.166 (Part C) and 423.180 to 423.186 (Part D)

Financial link

Medicare Advantage contracts with 4 or more stars get quality bonus payments

Data sources

HEDIS, CAHPS surveys, Health Outcomes Survey and CMS administrative data

What are Medicare Star Ratings?

CMS rates Medicare Advantage and Part D plans each year so beneficiaries can compare plan quality when they shop. Ratings are assigned at the contract level, so plans under the same contract share the same score, and they appear in Medicare Plan Finder in October, ahead of the annual enrollment period.

Medicare Advantage plans with drug coverage receive an overall rating plus separate Part C and Part D summary ratings. Stand-alone prescription drug plans receive a Part D rating.

How Star Ratings are calculated

Each contract is scored on dozens of measures. Each measure is converted to stars using cut points, then weighted and combined:

• Clinical quality and prevention, largely from HEDIS measures such as screenings and chronic condition management.
• Member experience, from the Consumer Assessment of Healthcare Providers and Systems (CAHPS) survey.
• Health outcomes, including measures from the Medicare Health Outcomes Survey.
• Drug plan measures, such as medication adherence for diabetes, hypertension and cholesterol drugs, calculated from prescription drug event data.
• Plan operations, such as appeals handling, call center performance, complaints and members leaving the plan.

Why Star Ratings matter

Star Ratings carry real money. Medicare Advantage contracts rated 4 stars or higher receive quality bonus payments that raise their benchmarks, and higher-rated plans keep a larger share of savings as rebates to fund extra benefits. Plans rated 5 stars can enroll members year-round through a special enrollment period, while contracts rated below 3 stars for three years in a row are flagged as low performing.

That makes medication adherence and preventive care measures a business priority: plans work with pharmacies and providers to close care gaps that affect ratings. CMS changes measures, weights and methods through annual rulemaking, and plans have challenged several years of ratings in court, so year-over-year comparisons need care.

Plan Star Ratings vs provider star ratings

Medicare Star Ratings for health and drug plans are different from the star ratings CMS publishes on Care Compare for hospitals, nursing homes, home health agencies and dialysis facilities. Those provider ratings use separate measures and methods, and a plan rating says nothing about any single hospital or physician in its network.