Measuring safety in health care settings remains challenging despite efforts to develop scorecards, focus on preventive strategies, and invest in safety infrastructure. This study compared the detection of adverse events in hospitals using the AHRQ patient safety indicators (PSIs), provider-reported events, and the IHI Global Trigger Tool. Investigators discovered that each method yielded significantly different results. For instance, only 6.2% of hospitalizations with a PSI also had a provider-reported event, and only 10.5% of provider-reported events had a PSI. Based on their findings, the authors suggest that measuring safety requires a multifaceted approach, but they caution about using such indicators for public reporting and performance comparisons. An AHRQ WebM&M commentary discusses the limitations of using PSIs for public reporting and hospital comparison purposes.