The Institute for Healthcare Improvement's Global Trigger Tool is being widely implemented as a means of identifying safety hazards through focused chart review. However, this Danish study calls its utility into question, as the investigators found poor interrater reliability when using the tool to identify adverse events in an oncology hospital. As a result, it was not possible to track error rates over time. Other commentators have recommended that hospitals use multiple complementary methods to detect safety problems, and this approach was recently endorsed in the AHRQ Making Health Care Safer II report.