Medicare calculates patient survey and outcomes data based on a patient survey called the Outpatient and Ambulatory Surgery Consumer Assessment of Healthcare Providers and Systems (OAS CAHPS) survey. This survey is administered to patients who receive care in a hospital outpatient department (HOPD) or an ambulatory surgical center (ASC). These surveys assess these providers’ performance in general, not just their performance in senior housing.

These star ratings are different from the consumer ratings that you see on websites for products like books, restaurants, or hotels that reflect averages of consumers' opinions. Since the star ratings rank all agencies from lowest to highest, some facilities will be ranked below others even though they're providing good quality care.

Survey data may not be available for every provider. More detail about the survey is available here: https://www.cms.gov/data-research/research/consumer-assessment-healthcare-providers-systems/outpatient-and-ambulatory-surgery-cahps.