Trigger tools have proved to be an effective method of screening for adverse events, with past research demonstrating their utility in the intensive care unit and pediatric hospitals. This study outlines the Institute for Healthcare Improvement Global Trigger Tool methodology and evaluates a refined process to improve the interrater reliability of the tool in practice. The authors found that a high level of interrater reliability was possible with well-trained primary (nonphysician) and secondary (physician) reviewers in this modified two-step approach.