At the Margins

Overall Hospital Quality Star Ratings: Answers to your frequently asked questions

by Jordan Kreke

The release earlier this year of Overall Hospital Quality Star Ratings for 3,662 providers sparked numerous questions from hospitals across the country: Which metrics affect overall star ratings? How are overall star ratings related to other CMS initiatives? Do overall star ratings impact reimbursement?

While detailed information is available online from CMS itself, we thought we would answer some common questions here.

What are CMS Overall Hospital Quality Star Ratings?

The Overall Hospital Quality Star Rating program classifies hospitals on a 1 to 5 star scale based on reported quality measures. CMS's stated goal is to facilitate informed choices for all consumers based on available hospital quality data. The first overall star ratings were reported in July of this year. They will be updated on a quarterly basis going forward, in conjunction with Hospital Compare data updates.

Will my Overall Hospital Quality Star Rating result in a reimbursement bonus or penalty from Medicare?

No. The overall star rating system is not a pay-for-performance program, so a hospital's overall star rating does not entail any payment adjustment.

However, many of the measures used to determine overall star ratings are also used in the Hospital Value-Based Purchasing Program (VBP), the Hospital-Acquired Conditions Reduction Program (HACRP), and the Hospital Readmissions Reductions Program (HRRP). These programs do have direct reimbursement impacts.

Are Overall Hospital Quality Star Ratings and HCAHPS Star Ratings basically the same?

No. While Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey data is included in the calculation of overall star ratings, it only accounts for 22% of a hospital's final rating. Overall Hospital Quality Star Ratings supplement HCAHPS Star Ratings by including outcomes, process, and efficiency measures not captured by HCAHPS.

How is my Overall Hospital Quality Star Rating calculated?

To calculate overall star ratings, CMS collects quality measures across seven quality domains and consolidates them into an overall summary score. To determine the number of stars awarded, each hospital's overall summary score is ranked against the scores of all other reporting hospitals.

The overall star rating process is statistically complex and designed to accommodate missing information, year-to-year variability in hospital reporting, and the addition and removal of measures over time. To explore CMS's methodology in greater depth, see CMS's Comprehensive Methodology Report.

Which quality measures are included and how are they weighted?

The Overall Hospital Quality Star Rating takes into account as few as 9 and as many as 57 measures from the Hospital Compare database. CMS categorizes quality measures into seven discrete measure groups, each covering a general quality domain.

The measure groups are: 1) mortality, 2) safety of care, 3) readmissions, 4) patient experience, 5) effectiveness of care, 6) timeliness of care, and 7) efficient use of medical imaging. (For a comprehensive list of metrics by measure group, see CMS's latest classification guide.)

Quality measures come from both the Inpatient Quality Reporting (IQR) and Outpatient Quality Reporting (OQR) programs, making the overall star rating system one of the few programs to consider quality measures from both sites.

CMS calculates summary scores for each measure group, which are then weighted and combined to yield the overall summary score, which determines the number of stars awarded. The weights of the measure group scores in the overall summary score are broadly consistent with the Hospital Value-Based Purchasing Program (VBP), although there are two significant differences.

First, overall star ratings factor in readmissions performance, while VBP does not. Second, VBP includes overall efficiency or cost measures, but overall star ratings only include imaging efficiency measures.

Measure group weights in Overall Star Ratings vs. Value-Based Purchasing

Measure Group
Number of Measures in Parentheses

FY 2017 HVBP Weight FY 2018 HVBP Weight Overall Star Rating Weight
 Outcomes - Mortality (7) 25% 25% 22%
Outcomes - Safety (8) 20% 25% 22%
Outcomes - Readmission (8) -- -- 22%
Patient Experience (11) 25% 25% 22%
Process - Effectiveness (11) 5% -- 4%
Process - Timeliness (7) -- -- 4%
Efficiency - Imaging (5) -- -- 4%
Efficiency - Cost 25% 25% --

CMS considers measure importance, consistency, policy priorities, and stakeholder input when determining measure group weights. CMS can revise the weighting quarterly, but so far there have been no changes.

What if my hospital does not report all measures?

Most hospitals will receive an overall star rating even if they do not report all possible quality measures. To be eligible for a rating, hospitals must report at least three measures within each of at least three measure groups, one of which must be an outcomes group.

If a hospital meets this threshold, then CMS will redistribute the weight of measure groups with insufficient data to the measure groups where sufficient measures have been reported. Hospitals that do not meet these minimum reporting thresholds will receive no star rating.

Do the overall star ratings include risk adjustment?

The quality measures used in calculating the final rating are adjusted for clinical risk, but they are not adjusted for the socioeconomic status of patients. CMS's own analysis of the first batch of overall star ratings from July 2016 illustrates a correlation between a hospital's rating and its safety-net, critical access, or DSH payment eligibility status.

In research with the National Quality Forum, CMS is currently evaluating the incorporation of socioeconomic risk adjustment in the overall star rating methodology.

Do hospitals' overall star ratings change significantly quarter to quarter?

The distribution of overall star ratings shifted only slightly between July 2016 and October 2016. Only 60 hospitals were downgraded, while 150 hospitals were upgraded. 85% of these upgrades were from two to three stars or from three to four stars. Only nine hospitals rose from four to five stars over this period.

Overall Hospital Quality Star Rating Distribution

It is possible that the removal of seven individual quality measures for the December 2016 update will yield more significant ratings changes. Once released, you can view the updated overall star ratings using our Data and Analytics Group's Star Ratings Map.

Overall Hospital Quality Star Rating Map
View the map in full size

How many more updates can we expect?

CMS will continue to evaluate and refine its overall star ratings methodology each quarter. We will update At the Margins accordingly.

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