The Centers for Medicare & Medicaid Services (CMS) Hospital Compare star ratings are widely used summaries of hospital quality that can influence patient choice and organizational reputation. A new study published in JAMA Health Forum sought to establish if methodological choices about the construction of the Centers for Medicare & Medicaid Services Hospital Compare star ratings are associated with the quality ratings of US hospitals.
The cross-sectional study used publicly available 2021 Hospital Compare data for 3,339 US hospitals from the October 2020 data release. Change in apparent hospital performance was assessed, arising when plausible alternatives to current methods are used for calculating star ratings in relation to individual measure standardization, domain derivation, and domain weighting. Three example changes were examined in detail, with more comprehensive changes considered using Monte Carlo simulation. Changes in centile of hospital ranks and in star rating overall were examined, as well as separately in CMS peer groupings defined by the number of reported quality domains. The study found different changes to the technical specification had differential outcomes, but even minor changes in specification could lead to substantial reclassification between adjacent performance categories.
Researchers concluded the Centers for Medicare & Medicaid Services Hospital Compare star ratings are very sensitive to methodological choices about how they are calculated, raising questions about their design and transparency.