Measuring errors and adverse events in health care remains challenging. Many hospitals use the AHRQ Patient Safety Indicators (PSIs) as a method to screen for potential events, with a past study suggesting associations between their presence and excess mortality, length of stay, and costs. This study applied selected PSIs to British hospital administrative data, used matched controls for analysis, and also compared findings to those reported in the US. Investigators discovered worse outcomes in cases with identified PSIs compared to matched controls, suggesting their utility in monitoring for safety events. There were noted differences between British and US data for specific indicators and their association with clinical outcomes, which are perhaps a greater reflection on the degree of event coding than on actual events.