This study used discharge data from hospitals in 11 states to see whether the rate of adverse patient safety events within the same hospital differed based on a patient's insurance status. Risk-adjusted rates of 13 AHRQ Patient Safety Indicators (PSIs) were measured. Patients with private insurance experienced significantly fewer adverse events compared to Medicare and Medicaid patients. However, these findings were not consistent across event types—Medicaid patients had lower event rates on two of the PSIs. These findings raise serious concerns about quality disparities within the same hospital, though there are many methodological limitations to the study such as the ability to accurately risk-adjust patients based on discharge data and whether PSIs provide a valid measurement of safety. A prior AHRQ WebM&M perspective reviewed different methods for measuring patient safety and the limitations of each tool.