The CMS Five-Star Rating System Explained

Why Star Ratings Were Created

Before the Five-Star system launched in 2008, families choosing a nursing home had to navigate raw inspection reports, staffing spreadsheets, and clinical quality data, technical documents that were essentially unreadable for non-experts. CMS created the star rating to translate this complexity into an intuitive 1-5 scale that any family could understand at a glance.

The system covers approximately 14,700 Medicare and Medicaid certified nursing homes, virtually every facility in the United States that accepts federal insurance. It does not cover assisted living facilities, memory care units that are not part of a certified nursing home, or home health agencies. Those have separate quality programs.

PlainNursing brings this data together in one searchable platform. Browse facilities by state, compare national rankings, or search for a specific facility to see its full rating breakdown.

Key Metric: The Overall Star Rating

What it tells you: The overall rating is a composite score from 1 (much below average) to 5 (much above average) that ranks the facility against all other nursing homes nationally. CMS uses a forced distribution so that approximately 20% of facilities fall into each star category. A 4-star facility is in the top 40% nationally; a 2-star facility is in the bottom 40%. The score provides a quick screening mechanism, families can immediately narrow a list of facilities to those above a quality threshold.

What it doesn't tell you: The overall rating is an average of averages. It masks critical variation between the three components. A facility with 5-star quality measures, 4-star staffing, but 1-star health inspections (indicating serious deficiencies found during surveys) might receive a 3-star overall rating, the same as a perfectly mediocre facility with 3 stars in every category. The number also cannot capture the daily experience of living in a facility: staff attitudes, food quality, activities, cleanliness, noise levels, and the general atmosphere.

How to use it: Use the overall rating as a first filter, not a final decision. Set a minimum threshold (most experts recommend 3 stars or above as a starting point) to create a shortlist, then dig into the three component ratings to understand the facility's specific strengths and weaknesses. Two 4-star facilities can look very different once you examine their components.

The Rating Formula Step by Step

Understanding the formula helps explain why some facilities have counterintuitive ratings. The calculation follows these steps:

1. Start with the Health Inspection rating. This is the foundation. The health inspection score is based on the three most recent standard surveys plus any complaint investigations, weighted so that the most recent survey counts most. Each deficiency receives a scope-and-severity score. The total weighted deficiency score is converted to a 1-5 star rating using a national percentile distribution.
2. Adjust for staffing. If the staffing rating is 4 or 5 stars, add one star to the health inspection base. If staffing is 1 star, subtract one star. If staffing is 2 or 3 stars, no adjustment.
3. Adjust for quality measures. If the QM rating is 5 stars, add one star. If QM is 1 star, subtract one star. If QM is 2, 3, or 4 stars, no adjustment.
4. Apply the staffing cap. If the staffing rating is 1 star, the overall rating cannot exceed 2 stars, regardless of how well the facility scores on inspections and quality measures. This reflects CMS's position that dangerously low staffing undermines all other quality measures.
5. Apply floor and ceiling. The result is capped at 5 stars and floored at 1 star.

This formula means health inspections are disproportionately influential. A facility cannot compensate for poor inspection results with excellent staffing and quality scores, the inspection rating sets the base, and adjustments can move the overall by at most +/-2 stars.

How the Adjustment Plays Out in Practice

As the table shows, the staffing component acts as both an accelerator and a brake. No other single component can override a 1-star staffing rating. See our understanding ratings guide for more on how to read the component breakdown on any facility page.

Component Deep Dive: What Drives Each Score

Health Inspections

The most heavily weighted component. State survey agencies conduct unannounced inspections approximately every 12 months (required within 15 months). Surveyors spend 3-5 days evaluating compliance across dozens of federal care standards. Deficiencies are categorized on a grid from A (isolated, no actual harm) to L (widespread, immediate jeopardy). Immediate jeopardy deficiencies carry approximately 50x the weight of low-severity findings.

Staffing

Based on Payroll-Based Journal (PBJ) data, actual payroll records, not self-reported estimates. CMS evaluates RN hours per resident day and total nursing hours per resident day, adjusted for resident case mix (sicker residents require more care hours). The staffing rating also includes an RN turnover measure and a weekend staffing measure added in 2022. Review staffing benchmarks in our staffing guide.

Quality Measures

Derived from the Minimum Data Set (MDS) - clinical assessments that facilities submit for every resident. Long-stay measures include rates of pressure ulcers, falls with major injury, antipsychotic medication use, UTIs, and physical restraint use. Short-stay measures include rehospitalization rates and improvement in functional ability. Each measure is risk-adjusted for resident health status, then combined into a composite score.

Practical Framework: Beyond the Star

1. Set a minimum threshold. Use 3 stars overall as a baseline filter. Below 3 stars puts the facility in the bottom 40% nationally. Create a shortlist of 5-10 facilities within your geographic area that meet this threshold.
2. Examine component ratings separately. For each facility on your shortlist, look at health inspection, staffing, and quality measure ratings individually. Prioritize facilities with at least 3 stars in staffing (research shows staffing levels are the strongest predictor of daily care quality) and no recent immediate jeopardy deficiencies.
3. Check for abuse flags and recent penalties. CMS displays an "Abuse Icon" for facilities with substantiated abuse citations. Also check for recent fines, payment denials, and state monitoring activity, these appear on the Medicare.gov detail page for each facility.
4. Visit in person. Data cannot replace an on-site visit. Pay attention to staff-to-resident interactions, cleanliness, odor, activity levels, and whether residents appear engaged or isolated. Visit at different times of day, weekday dinner and weekend mornings reveal different staffing realities than a scheduled Tuesday morning tour.

Frequently Asked Questions