Hospital Compare overall hospital rating

The Hospital Compare overall hospital rating summarizes up to 57 quality measures across 7 areas of quality into a single star rating for each hospital. Once reporting thresholds are met, a hospital’s overall hospital rating is calculated using only those measures for which data are available. This may include as few as 9 or as many as 57 measures. The average is about 39 measures. Hospitals report data to the Centers for Medicare & Medicaid Services - Opens in a new window through the Hospital Inpatient Quality Reporting (IQR) Program - Opens in a new window Exit Disclaimer - Opens in a new window and the Hospital Outpatient Quality Reporting (OQR) Program - Opens in a new window Exit Disclaimer - Opens in a new window. Star ratings are not calculated for Veterans Health Administration (VHA) hospitals.

The methodology uses a statistical model known as a latent variable model. Seven different latent variable models are used to calculate scores for 7 groups of measures.

1. Mortality
2. Safety of Care
3. Readmission
4. Patient Experience
5. Effectiveness of Care
6. Timeliness of Care
7. Efficient Use of Medical Imaging

A hospital summary score is then calculated by taking the weighted average of these group scores. If a hospital is missing a measure category or group, the weights are redistributed amongst the qualifying measure categories or groups.

Finally, the overall hospital rating is calculated using the hospital summary score.

Only hospitals that have at least 3 measures within at least 3 measure groups or categories, including one outcome group (mortality, safety, or readmission), are eligible for an overall hospital rating. Not all hospitals report all measures. Therefore, some hospitals may not be eligible for an overall rating.

The comprehensive methodology report - Opens in a new window Exit Disclaimer - Opens in a new window provides additional detail on the methodology used to calculate the Hospital Compare overall hospital rating.

National distribution of overall hospital ratings

The following table shows the national distribution of the overall rating based on December 2017 results.

Additional information

The methodology for calculating the overall hospital ratings was developed with input from stakeholders and members of the public. Detailed information on the methodology is available on QualityNet - Opens in a new window External Link icon.

Questions about the Hospital Compare overall hospital rating may be submitted to: cmsstarratings@lantanagroup.com.