Nursing home star ratings explained

Nearly every nursing home that takes Medicare or Medicaid gets a rating from 1 to 5 stars from the Centers for Medicare & Medicaid Services (CMS). The stars are useful, but they're easy to over-read. Here's what's behind them.

Three ratings feed the overall score

Health inspections. This one comes from what state inspectors found during recent standard inspections and complaint investigations, with newer findings counting more. Inspections are tougher in some states than others, so homes are only compared with other homes in the same state. A 4-star inspection rating in one state isn't directly comparable to a 4 in the next state over.

Staffing. Based on how many hours of registered nurse time and total nursing time each resident gets per day, taken from payroll records and adjusted for how much care the residents need. Weekend staffing and staff turnover are part of it too.

Quality measures. A set of clinical results: for long-term residents, things like falls with serious injury, pressure ulcers and antipsychotic use. For short-stay rehab patients, whether they regained function, ended up back in the hospital or went to the emergency room.

How the overall rating is built

CMS doesn't just average the three. It starts from the inspection rating and then nudges it:

• up one star if staffing is 4 or 5 stars and higher than the inspection rating, or down one star if staffing is 1 star
• up one star if quality measures are 5 stars, or down one if they're 1 star
• a home with a 1-star inspection rating can't be raised by more than one star in total

In practice, the overall rating mostly reflects inspections. That's on purpose, since inspections are the one part the home doesn't report about itself.

Where the stars can mislead

• Much of the quality measure data comes from assessments the home fills out itself.
• Everything describes the past. An inspection might be more than a year old.
• New owners or a new administrator can change a home fast, in either direction. Check whether ownership changed recently.
• In small homes, a couple of residents or one bad inspection can move the rating a lot.

We treat the stars as a way to build a shortlist, not to make the final call. The inspection reports and a visit tell you far more.