Guide · Quality measures
Hospital Quality Measures Explained
What each quality metric actually measures and which ones matter most for your situation.
The short answer
No single number captures hospital quality: infection rates show safety, readmissions show discharge quality, mortality shows outcomes for serious conditions, and patient experience shows communication, the measure that matters depends on why you are going in.
By the numbers
What the CMS data shows
- 5,426
- Hospitals tracked
- 3.1 / 5
- Avg CMS star rating
- 288 · 10%
- Five-star hospitals
National CMS star-rating distribution
How all 2,866 rated Medicare hospitals break down across the 1–5 star scale
- 5★ 288
5-star hospitals
288 hospitals
- 4★
4-star hospitals
765 hospitals
- 3★
3-star hospitals
935 hospitals
- 2★
2-star hospitals
649 hospitals
- 1★ 229
1-star hospitals
229 hospitals
What this shows Most hospitals cluster in the 3–4 star range; only 10% reach five stars and a similar share sit at one star, the headline rating is a relative ranking, not a pass/fail mark.
According to the Centers for Medicare & Medicaid Services (CMS), these figures cover 5,426 Medicare-certified hospitals as of March 2026, read our methodology for how the data is compiled.
Every measure here is defined by the Centers for Medicare & Medicaid Services (CMS) and drawn from Hospital Compare data for 5,426 hospitals, refreshed March 2026, see our methodology.
Safety Measures, Preventing Harm
Safety measures track how well hospitals prevent patients from being harmed during their stay. These are arguably the most actionable measures because they reflect hospital practices that directly affect every patient:
- Hospital-acquired infections: Six types of infections tracked by CMS. These are largely preventable with proper protocols, hand hygiene, sterile technique, catheter management. Hospitals with low infection rates have strong infection prevention programs.
- Patient safety indicators (PSIs): Complications like post-operative sepsis, pressure ulcers, and accidental punctures. These composite measures capture a range of adverse events that shouldn't happen during routine care.
When choosing a hospital for any procedure involving an overnight stay, infection rates should be a top consideration. Check these on any hospital page on PlainHospital.
Outcome Measures, What Happened to Patients
Outcome measures track the most important results:
- 30-day mortality: How often patients die within 30 days of admission for specific conditions (heart attack, heart failure, stroke, pneumonia, COPD). Risk-adjusted for patient severity. The most consequential measure for high-risk conditions.
- 30-day readmission: How often patients return to the hospital within a month. High readmission rates suggest the hospital may be discharging patients too early, providing inadequate discharge instructions, or failing to coordinate follow-up care.
- Complication rates: For specific procedures (hip/knee replacement, coronary bypass), CMS tracks complication rates including infections, blood clots, and mechanical failures.
Patient Experience, The Human Side
HCAHPS surveys capture the patient's experience, not clinical outcomes, but how they felt about their care:
- Doctor communication: Did doctors explain things clearly, listen carefully, and treat you with courtesy?
- Nurse communication: Same dimensions for nursing staff, often the most frequent point of contact.
- Responsiveness: How quickly staff responded when you needed help.
- Environment: Room cleanliness, noise levels at night.
- Discharge information: Were you given clear instructions about what to do after leaving?
- Overall rating: Would you recommend this hospital? (0-10 scale)
Patient experience measures correlate with clinical outcomes, hospitals with better communication tend to have better adherence to treatment plans and lower readmission rates. But they also reflect factors outside clinical quality (facilities, parking, food).
Reading the Standardized Infection Ratio (SIR)
SIR is the actual count of infections divided by the predicted count, given the hospital's case mix. A SIR of 1.00 means the hospital had exactly as many infections as predicted. A SIR of 0.50 means it had half the predicted number, a strong result. A SIR of 1.50 means it had 50% more than predicted, a warning sign.
Risk-adjustment basics
CMS uses statistical models that account for patient age, comorbidities, and severity-of-illness scores derived from claims data. This is essential because hospitals treating the sickest patients would otherwise look the worst regardless of actual care quality.
Where readmission and mortality diverge
Mortality rates and readmission rates measure different things. A hospital may have low mortality (good acute care) but high readmission (poor discharge planning), or vice versa. Both signals matter for different decision criteria.
Volume thresholds for reporting reliability
CMS requires minimum case volumes before publishing risk-adjusted measures. For most procedures the floor is around 25 cases over the measurement window. Below this, results are suppressed because confidence intervals would be too wide for fair public comparison.
| Measure | Better Direction | Typical Range | Most Relevant For |
|---|---|---|---|
| CLABSI SIR | Lower | 0.5 – 1.5 | ICU stays, central-line procedures |
| 30-day readmission | Lower | 15% – 22% | Heart failure, COPD, pneumonia |
| 30-day mortality (AMI) | Lower | 12% – 17% | Heart attack patients |
| HCAHPS overall | Higher | 60% – 80% top-box | All inpatient admissions |
Worked example: comparing CLABSI rates between two ICUs
Hospital X reports a CLABSI SIR of 0.65 with a 95% confidence interval of 0.45 – 0.92. Hospital Y reports a SIR of 1.10 with a 95% confidence interval of 0.85 – 1.40. The point estimates differ by about 70%, but more importantly Hospital X's upper bound (0.92) sits below Hospital Y's lower bound (0.85) - a true statistical separation. Translated to clinical terms: per 1,000 central-line days you'd expect roughly 35% fewer infections at Hospital X versus 10% more than predicted at Hospital Y. For an ICU stay involving central lines, that's a real and consequential difference, not noise.
Which Measures Matter Most?
It depends on your situation:
- Having surgery? Prioritize infection rates and procedure-specific complication data.
- Heart attack or stroke? Focus on mortality rates and timely treatment measures for that condition.
- Having a baby? Look at maternal health measures, C-section rates, and patient experience.
- Chronic condition management? Readmission rates and care coordination measures are most relevant.
- General hospital stay? Safety (infection rates) and patient experience give the best overall picture.
Browse PlainHospital's rankings to find top-rated hospitals in your state, or search for a specific hospital to see all its quality measures.
Frequently Asked Questions
What are hospital-acquired infections (HAIs)?
HAIs are infections patients get while receiving treatment in a hospital for another condition. CMS tracks six types: central line-associated bloodstream infections (CLABSI), catheter-associated urinary tract infections (CAUTI), surgical site infections (SSI), MRSA bacteremia, C. difficile infections, and others. Lower rates indicate better infection prevention practices.
What does the readmission rate measure?
The 30-day readmission rate measures how often patients are readmitted to any hospital within 30 days of being discharged. High readmission rates may indicate premature discharge, inadequate discharge planning, or poor post-discharge follow-up. CMS tracks readmissions for heart attack, heart failure, pneumonia, COPD, hip/knee replacement, and coronary artery bypass surgery.
What is HCAHPS?
The Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) is a standardized patient satisfaction survey. It asks about communication with doctors and nurses, responsiveness of staff, pain management, medication communication, discharge information, cleanliness, quietness, and overall rating. Results are publicly reported and factor into star ratings.
Are mortality rates the most important measure?
Mortality rates are among the most important for high-risk conditions (heart attack, stroke, surgery). However, for many hospital visits, childbirth, joint replacement, minor surgery, mortality is extremely rare and other measures (infection rates, readmissions, patient experience) are more relevant to the typical patient experience.
What does "better/worse/same as national average" mean?
CMS compares each hospital's performance to the national rate using statistical confidence intervals. "Better than national" means the hospital's rate is statistically significantly better (not just slightly better). "No different" means the hospital performs within the expected range. "Worse" means statistically significantly worse. Most hospitals fall in the "no different" category for most measures.
Can I see quality data for specific procedures?
CMS publishes procedure-specific data for common surgeries (hip replacement, knee replacement, coronary bypass) including complication rates and readmission rates. PlainHospital shows available procedure-level data on each hospital's page. For rare or specialized procedures, ask the hospital directly about their volume and outcomes.
Sources
- CMS, Hospital Compare Quality Measures
- CMS, HCAHPS Patient Experience Survey
- CDC, National Healthcare Safety Network (HAI data)
This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider for guidance specific to your medical needs.
