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Star Ratings

Health Outcomes Survey (HOS) and Medicare Star Ratings

Medicare Star Ratings Overview

The Centers for Medicare & Medicaid Services (CMS) developed the Medicare Star Ratings in order to help consumers compare health plans and providers based on quality and performance, and to reward top-performing health plans. The Medicare Plan Finder (MPF) tool allows consumers to search for health plans in their geographic area and compare cost estimates and coverage information. CMS rates the relative quality of service and care provided by Medicare Advantage Organizations (MAOs) based upon a five-star rating scale that utilizes the contract level HOS measures combined with other measurement results. The Medicare Star Ratings help people with Medicare compare Medicare Advantage (MA) plans, help educate consumers on quality, and make quality data more transparent and comparable among plans. Up to 44 unique quality measures are included in the 2021 Medicare Part C and D Star Ratings, including success in providing preventive services, managing chronic illness, access to care, Healthcare Effectiveness Data and Information Set (HEDIS®) measures, the Consumer Assessment of Healthcare Providers and Systems (CAHPS©) survey, and responsiveness.

HOS Measures in the Star Ratings

The Medicare Part C Star Ratings include six contract level HOS measures: three measures of functional health and three HEDIS Effectiveness of Care measures. In the 2022 and 2023 HOS Star Ratings, the three functional health measures are for display only, and the following three HEDIS Effectiveness of Care measures are included in the Medicare Part C Star Ratings:

  • Monitoring Physical Activity
  • Improving Bladder Control
  • Reducing the Risk of Falling

The HEDIS Effectiveness of Care measures are collected from the HOS in a series of questions that ask health plan members about information and care they receive from their health care providers. Beginning in 2021, these measures are reported in each MAO’s annual HEDIS HOS Effectiveness of Care Report that is posted on the Health Plan Management System (HPMS). Prior to 2021, the measures were previously reported in each MAO's annual HOS Baseline Report. The measures are obtained from the combined data for the baseline cohort and a follow up cohort from the same measurement year (i.e., a round of data). Questions are collected to derive the following three HEDIS measures: Management of Urinary Incontinence in Older Adults, Physical Activity in Older Adults, and Fall Risk Management. These rates are utilized by CMS for the Medicare Part C Star Ratings: Improving Bladder Control is the Treatment of Urinary Incontinence rate, Monitoring Physical Activity is the Advising Physical Activity rate, and Reducing the Risk of Falling is the Managing Fall Risk rate.

HOS Display Measures

The following HOS measures are currently for display only, and are not incorporated in the Star Ratings calculations:

  • Improving or Maintaining Physical Health
  • Improving or Maintaining Mental Health
  • Physical Functioning Activities of Daily Living

Two of three functional health display measures are derived from the Veterans RAND 12-Item Health Survey (VR-12) portion of the HOS, which serves as the core measure for the physical component summary (PCS) and mental component summary (MCS) scores. These measures are reported in each MAO’s annual HOS Performance Measurement Report that is posted on the HPMS. These results are derived from a combination of case-mix adjusted PCS and MCS change scores and death status based on the baseline and two-year follow up surveys. The Improving or Maintaining Physical Health measure is the combined Physical Health Percent Better+Same result, and the Improving or Maintaining Mental Health measure is the combined Mental Health Percent Better+Same result. The third functional health display measure, Physical Functioning Activities of Daily Living (PFADL) is derived from the combination of two physical functioning questions from the VR-12 (limitations in moderate activities or climbing stairs) and six activities of daily living (ADL) questions (difficulty with bathing, dressing, eating, walking, getting in and out of chairs, or using the toilet).

HOS Module on HPMS

CMS continues to make enhancements to the HPMS HOS module to increase functionality and improve overall usability. When accessing the HOS module under “Quality and Performance,” HPMS users will note a new HOS dashboard with an “Announcement” section and seven “Action” choices. From “Star Ratings Validations,” MAOs may select the Star Ratings Measures report to review their HOS Star Ratings results from the HEDIS HOS and Performance Measurement reports and to review their MAO’s Star Ratings data during the plan preview periods. The results include the functional health measures and the HEDIS Effectiveness of Care measures for the selected cohorts of data (Cohort 13 and future cohorts). Users may also select the Improving or Maintaining Physical Health (PCS) report and the Improving or Maintaining Mental Health (MCS) report. The corresponding information for the two functional health measures is displayed for all completed cohorts beginning with Cohort 1.

The “Aggregate Score Analysis” provides a table review of percentages for physical health and mental health measures from the HOS Performance Measurement report. The table under Physical Health includes: Physical Component Summary Score; Percent Reporting Health Now Compared to 1 Year Ago (Better/Same); Percent Reporting Problems with 2 or More ADLs; Percent Reporting 2 or More Chronic Diseases; Percent Reporting 14 or More Physically Unhealthy Days; and Percent Reporting Obesity with 30+ Body Mass Index (BMI). The table under Mental Health includes: Mental Component Summary Score; Percent Reporting Depressive Symptoms; and Percent Reporting 14 or More Mentally Unhealthy Days. In 2022, Percent Deceased Within 2 Years of Baseline Survey will be moved from the Physical Health table to a new table for Other Health. Additionally, three new items will be included under the Other Health table: Reporting 14 or More Days with Activity Limitations Due to Poor Health; Percent Reporting 7-8 Hours of Actual Sleep; and Percent Reporting Very Good Overall Sleep Quality. 

The “Performance Measurement,” “HEDIS HOS,” “Baseline,” and “HOS-M Feedback” selections provide links to the corresponding reports and the “HOS Program” selection provides general information about the HOS program and reports. 

Medicare Star Ratings Timeline

CMS posted the 2022 Medicare Part C Star Ratings in October 2021. The HOS 2018-2020 Cohort 21 Merged Baseline and Follow Up data set were used for the three functional health measures, and the combined HOS 2020 Cohort 23 Baseline and 2020 Cohort 21 Follow Up data set were the source for the three 2020 HEDIS Effectiveness of Care measures (see yellow highlighted text in the Timeline Table below).

The 2023 Medicare Part C Star Ratings will be posted in October 2022. The HOS 2019-2021 Cohort 22 Merged Baseline and Follow Up data set will be used for the three functional health measures, and the combined HOS 2021 Cohort 24 Baseline and 2021 Cohort 22 Follow Up data set will be used for the three 2021 HEDIS Effectiveness of Care measures (see green highlighted text in the Timeline Table below).

Information about best practices in promoting quality preventive health care for the elderly and developing intervention strategies to impact patient outcomes is available in the 2012 MAO resource guide and 2011 technical report on the functional status of older adults in the Trainings section.

Additional information about the Medicare Star Ratings can be found on the CMS Star Ratings website. For any questions related to Medicare Part C and D Star Ratings, you may send an email inquiry directly to PartCandDStarRatings@cms.hhs.gov.

The Medicare HOS Survey Administration and Star Ratings Timeline Table below contains information about the HOS cohorts related to data collection, report dissemination, and the HOS results included in the CMS Medicare Part C Star Ratings. The complete table of all HOS cohorts since 1998 is available in the Program page.

Medicare HOS Survey Administration and Star Ratings Timeline
  Data Collection HOS Reports Medicare Part C Star Ratings
  Baseline Follow Up Baseline Follow Up 2-yr PCS/MCS Change/ PFADL Change HEDIS HOS Measures Rating Year
2024 Cohort 27 Cohort 25 Cohort 26 Cohort 24 2020-2022 Cohort 23 2022 Cohort 25 Baseline & 
2022 Cohort 23 Follow-up
2023 Cohort 26 Cohort 24 Cohort 25 Cohort 23 2019-2021 Cohort 22 2021 Cohort 24 Baseline & 
2021 Cohort 22 Follow-up
2022 Cohort 25 Cohort 23 Cohort 24 Cohort 22 2018-2020 Cohort 21 2020 Cohort 23 Baseline & 
2020 Cohort 21 Follow-up
2021 Cohort 24 Cohort 22 Cohort 23 Cohort 21 2017-2019 Cohort 20 2019 Cohort 22 Baseline & 
2019 Cohort 20 Follow-up
2020 Cohort 23 Cohort 21 Cohort 22 Cohort 20 2016-2018 Cohort 19 2018 Cohort 21 Baseline & 
2018 Cohort 19 Follow-up


Three HEDIS Effectiveness of Care Measures collected by HOS are calculated from the combined round of baseline and follow up data by reporting year: Management of Urinary Incontinence in Older Adults; Physical Activity in Older Adults; and Fall Risk Management.

This page was last modified on 06/22/2022

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