**June 2007 UPDATE**

In Appendix C on page 35, the calculation for the measure "Percent of admissions with an adverse event" was missing the denominator (Total records reviewed). The calculation has now been updated in the paper, to read: "Number of records with at least 1 event/Total records reviewed x 100=Percent of admissions with an adverse event."

How to cite this paper:

Griffin FA, Resar RK. IHI Global Trigger Tool for Measuring Adverse Events. IHI Innovation Series white paper. Cambridge, MA: Institute for Healthcare Improvement; 2007. (Available on www.IHI.org)

Traditional efforts to detect adverse events have focused on voluntary reporting and tracking of errors. However, public health researchers have established that only 10 to 20 percent of errors are ever reported and, of those, 90 to 95 percent cause no harm to patients. Hospitals need a more effective way to identify events that do cause harm to patients in order to quantify the degree and severity of harm, and to select and test changes to reduce harm.

The IHI Global Trigger Tool for Measuring Adverse Events provides an easy-to-use method for accurately identifying adverse events (harm) and measuring the rate of adverse events over time. Tracking adverse events over time is a useful way to tell if changes being made are improving the safety of the care processes. The Trigger Tool methodology includes a retrospective review of a random sample of patient records using “triggers” (or clues) to identify possible adverse events. Many hospitals have used this tool to identify adverse events, to measure the level of harm from each adverse event, and to identify areas for improvement in their organizations. It is important to note, however, that the IHI Global Trigger Tool is not meant to identify every single adverse event in a patient record. The recommended time limitation for review and the random selection of records are designed to produce a sampling approach that is sufficient for the design of safety work in the hospital.

The Institute for Healthcare Improvement (IHI) formed the Idealized Design of the Medication System (IDMS) Group in May 2000. The group of 30 physicians, pharmacists, nurses, statisticians, and other professionals established an aim to design a medication system that is safer by a factor of 10 and more cost-effective than systems currently in use. The Trigger Tool for Measuring Adverse Drug Events was initially developed by this group and provided the basis for development of other subsequent Trigger Tools.

This white paper provides comprehensive information on the development and methodology of the IHI Global Trigger Tool, with step-by-step instructions for using the tool to accurately identify adverse events (harm) and measure the rate of adverse events over time.