Trigger tools are a widely used method for detecting safety hazards in hospitalized patients. However, there is limited literature on using trigger tools in pediatric patients, as most existing tools were developed in adult patient populations. This study reports on the development and refinement of a novel trigger tool for hospitalized children. In testing at academic and community hospitals, the tool was found to accurately identify adverse events. Although other studies have raised concerns about the interrater reliability of trigger tools, in this study, agreement between reviewers regarding the presence of an adverse event improved with increased experience with the tool. The authors state that the tool can be used for measurement purposes, allowing institutions to track their performance over time and compare rates of safety events across institutions.