How to Read a Hospital Grade (and What CMS Star Ratings Leave Out)

Our hospital grade combines four things CMS publishes for every Medicare-certified hospital: the overall star rating, and the counts of mortality, safety and readmission measures on which the hospital is better or worse than the national rate.

What the metrics mean

• Mortality — 30-day death rates for heart attack, heart failure, pneumonia, stroke, COPD, bypass surgery and a surgical-complications measure, adjusted for how sick patients were.
• Safety — hospital-acquired infections (central line, catheter, surgical site, MRSA, C. diff), complications and a composite of serious events.
• Readmission — unplanned returns within 30 days for the same conditions plus hip and knee replacement.
• Overall rating — CMS's own 1–5 stars, which also folds in patient experience and timeliness.

Why a well-known hospital can be graded C

The measures are outcomes for common conditions, adjusted for patient risk but not for reputation, research or rare specialities. A teaching hospital that takes the most complex transfers can be average on these and still be where you want a rare operation done.

How to use it

1. In an emergency, go to the nearest emergency department.
2. For planned care, shortlist A and B hospitals in your network, then ask about volume and outcomes for your specific procedure.
3. Check the safety line: infections and complications are the measures you personally can least control.