Patients' reports of safety concerns can reveal adverse events that would not be identified otherwise. In this cluster-randomized trial of patient engagement, patient volunteers read and classified incident reports submitted by hospitalized patients enrolled in the study. Following classification by patients, reports underwent a standardized, validated review by multiple researchers to determine if the event constituted a patient safety incident. Overall, about one-third of patient-reported concerns were deemed to be patient safety incidents. Medication safety issues were the most prevalent concerns. The authors conclude that patient reporting of safety events lends a unique and necessary perspective to error reporting. A previous PSNet perspective highlighted the advantages to and limitations of engaging patients in patient safety.