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CMS releases hospital quality star ratings

Revised methodology for the rating system was finalized in the 2021 outpatient prospective payment system final rule. 

Susan Morse, Managing Editor

(Photo by John Fedele/Getty Images)(Photo by John Fedele/Getty Images)

The Centers for Medicare and Medicaid Services on Wednesday released the overall hospital quality star ratings that now include new methodology in five measure groups.

CMS rated over 4,500 hospitals from one to five stars, with five representing the highest quality rating.

Of 4,586 hospitals, 13.5%, or 455 hospitals, received five stars; 988 received four stars; 1,018 received three stars; 690 received two stars; and 204 received one star.

For more than a quarter of hospitals, 1,181, no information was available.

This compares to January 2020 data, when of the 5,340 hospitals listed, 396 received five stars; 1,132 received four stars; 1,108 got three stars; 710 received two stars; and 226 got one star. Another 1,761 had no rating information available.


CMS uses star ratings for its Compare website for consumers to choose highly rated hospitals and other providers in their area.

Star ratings for hospitals are not directly related to financial reimbursement, but many of the measures used to determine the overall star ratings are also used in other programs, such as the Hospital Value-Based Purchasing Program, that do directly affect reimbursement.

The star rating summarizes a variety of measures across five areas of quality into a single star rating for each hospital. Once reporting thresholds are met, a hospital's overall star rating is calculated using only those measures for which data are available. The average is about 37 measures.

New methodology measure groups are for mortality, safety of care, readmission, patient experience and timely and effective care.

Only hospitals that have at least three measures within three measure groups, with at least one of those groups being mortality or safety of care, are eligible for an overall star rating. Not all hospitals report all measures, so some hospitals may not be eligible.

For each hospital, a summary score is calculated by taking the weighted average of the hospital's scores for each measure group or category. Mortality is weighted at 22%, safety at 22%, readmission at 22%, patient experience at 22%, and timely and effective care at 12%.


The star ratings includes a variety of the more than 100 measures CMS publicly reports, divided into five measure groups or categories. 

The revised methodology was finalized in the 2021 outpatient prospective payment system final rule.

CMS did not update the hospital star ratings this past January, so as to allow time to review comments and finalize proposed changes to the new star ratings methodology.

Under an interim final rule released in August, CMS did not use quality data from January 1 through June 30. CMS said it used October data to calculate April 2021 overall star ratings. 


American Hospital Association Senior Vice President, Public Policy Analysis and Development Ashley Thompson said, "Today's star ratings update is an improvement that will likely make the ratings more useful for both patients and hospitals. For example, we are pleased that CMS is now calculating hospital performance by simple averages, rather than using a previously flawed approach. In addition, we appreciate that CMS reorganized some of the measures so individual topics wouldn't carry an undue amount of weight in the determination of star ratings. These changes have made the star ratings easier to interpret, more insightful for hospitals working to improve their quality of care, and more balanced in favor of high-priority topics, like infections. 

"However, certain changes might not have the effect that CMS hopes, and there remain flaws in the methodology that CMS must address. We remain concerned that CMS's failure to account for social risk factors in calculating performance on measures like readmissions biases the ratings against those hospitals caring for more vulnerable patients. Further, while we agree with the intent of CMS's new peer grouping approach – that is, to create a more level playing field between hospitals offering differing levels of care – we believe it needs improvement to ensure it fosters equitable comparisons. Finally, and importantly, because the star ratings methodology has changed so frequently and significantly since its inception, comparing a hospital's latest overall star rating with a previous rating could be very misleading."  

Twitter: @SusanJMorse
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