What the star rating is
CMS takes the quality measures it collects from every Medicare-certified hospital, groups them into five categories — mortality, safety, readmission, patient experience and timely & effective care — then combines those groups into a single score from 1 to 5 stars. It is designed as a starting point for comparison, not a verdict.
How the stars are distributed
Of the 5,419 hospitals in the current CMS release, 3,174 have an overall star rating. Here is how they fall:
| Rating | Hospitals | Share of rated |
|---|---|---|
| 5 stars — Much above average | 384 | 12% |
| 4 stars — Above average | 946 | 30% |
| 3 stars — Average | 985 | 31% |
| 2 stars — Below average | 661 | 21% |
| 1 star — Much below average | 198 | 6% |
Why 2,245 hospitals have no star
That is 41% of all hospitals — and it is almost never a quality signal. CMS withholds the overall rating when:
- The hospital reported too few measures, or too few cases per measure, for the result to be statistically reliable. This is the usual reason, and it mostly affects small rural hospitals.
- It is a critical access hospital, which serves a small rural community under a different Medicare payment system.
- It is a psychiatric or children's hospital. The measures behind the star rating are built around adult medical and surgical care, so they do not apply.
- It is a federal hospital — VA or Department of Defense facilities report through separate systems.
For any of these hospitals, the individual measures on its profile page are still published and are often more informative than a summary star would have been.
The measures in this category
These are the measures CMS publishes in this category, with the national median across all reporting hospitals for context.
| Measure | Better is | National median |
|---|---|---|
| Heart attack deaths Of patients admitted for a heart attack, the share who died within 30 days — counted wherever they died, including at home. | Lower | 11.8% |
| Heart failure deaths Death rate within 30 days for patients admitted with heart failure. | Lower | 11% |
| Pneumonia deaths Death rate within 30 days for patients admitted with pneumonia. | Lower | 15.2% |
| COPD deaths Death rate within 30 days for patients admitted with chronic obstructive pulmonary disease. | Lower | 8.5% |
| Stroke deaths Death rate within 30 days for patients admitted with a stroke. | Lower | 11.6% |
| Bypass surgery deaths Death rate within 30 days after coronary artery bypass graft surgery. | Lower | 2.3% |
| Overall death rate Hospital-wide death rate across all conditions, adjusted for how sick patients were on arrival. The broadest mortality measure CMS reports. | Lower | 3.9% |
| Deaths from treatable complications Surgical patients who died from a complication that could usually have been caught and treated in time. Sometimes called "failure to rescue". | Lower | Not enough hospitals report it |
Medians calculated by hospiguide.org from the current CMS release, across hospitals that reported each measure. We use the median rather than the mean because these measures are skewed — a handful of outliers pull an average far from the typical hospital.
Where to go next
Browse hospitals by state to see these measures for a specific hospital, or compare two hospitals side by side. For the official source, see Medicare.gov Care Compare.