Detecting and measuring patient safety hazards remains challenging, but assessing the potential for a given safety problem to cause harm is even more difficult. Experts therefore sought to achieve consensus around an all-cause pediatric harm measurement tool using a modified Delphi process. They vetted 108 possible trigger tools that can indicate an incipient safety risk, including use of reversal agents for high-risk medications and diagnosis of health care–associated infections. After multiple rounds of discussion and evidence review, investigators produced a list of 51 triggers, which they plan to pilot test. The authors assert that this work is the first step toward identifying harm to pediatric patients in real-time.