What the CMS Five-Star Rating Really Measures

The star rating on Medicare's Care Compare is the closest thing American eldercare has to a universal grade, and it is genuinely useful. It is also narrower than most families assume.

How it is built

The overall rating combines three separate ratings:

• Health inspections. Built from the last three years of standard surveys plus complaint investigations, weighted so recent findings and more serious findings count for more. This component is scored relative to other homes in the same state.
• Staffing. Nursing hours per resident per day, adjusted for how sick the residents are, drawn from payroll data submitted to CMS rather than self-reported estimates. RN hours are weighted separately.
• Quality measures. Resident outcomes from clinical assessments — pressure ulcers, falls with injury, urinary tract infections, antipsychotic use, and how short-stay residents fared after discharge.

The inspection rating sets the baseline; strong staffing and quality can raise the overall rating, and weak ones can lower it.

What it captures well

The staffing component is now payroll-based, which was a real improvement — homes can no longer simply report the numbers they wish were true. And the inspection component is grounded in what trained surveyors actually found on site, which is the best evidence available.

The four blind spots

1. It is graded on a curve, by state. The inspection rating compares homes to others in the same state. A four-star home in a state with lenient surveying and a four-star home in a strict one are not equivalent. Compare across state lines with care.
2. Quality measures are largely self-reported. The clinical assessments feeding this component are completed by the home itself. Research has repeatedly found homes whose self-reported quality scores sit well above what their inspection records would suggest.
3. It is slow. Ratings lean on up to three years of survey history. A home that was sold last year, lost its nursing leadership and now runs on agency staff can carry a rating earned by a management team that has long since left.
4. It says nothing about ownership. Who owns a home, how many others they own, and how those others perform is not in the rating at all — even though it is often the best predictor of where the home is heading.

Why we publish a separate grade

ElderGrade does not replace the star rating — you will find it on every profile here, because it is genuinely informative. Our grade exists to surface what the stars leave out: staff turnover, the weekend staffing gap, the actual severity of recent citations rather than a curved score, enforcement history in dollars, and ownership. Where a finding is serious enough that no amount of good staffing should offset it — an abuse citation, Special Focus status, an immediate-jeopardy finding — our grade is capped outright rather than averaged away.

The full formula, including every weight and every cap, is published on How we grade. Use both ratings. Where they disagree, that disagreement is itself information worth asking about.