Identifying adverse events in real time remains a patient safety challenge. Trigger tools—structured data values such as abnormal test results or administration of a specific medication reversal agent—can detect a potential adverse event. Investigators sought to refine the Institute of Healthcare Improvement Global Trigger Tool to more efficiently and accurately identify preventable adverse events among hospitalized patients. They surmised that care escalation would be more likely to be due to a preventable patient safety problem than underlying illness among younger patients with fewer comorbid conditions. Among these patients, they applied a modified trigger tool to identify cases of possible adverse events. Two physicians then reviewed the records for triggered cases to determine whether a preventable adverse event occurred, as in prior studies. About half of trigger-positive cases represented preventable adverse events, and there was moderate agreement between the two reviewers. The authors conclude that this modified trigger tool and record review procedure advances the methodology of adverse event identification in hospitalized patients.