The findings of a consensus committee created to address the definition, measurement, and identification of error in emergency medicine (EM) are presented. The literature of error measurement in medicine is also reviewed and analyzed. The consensus committee recommended adopting a standard set of terms found in the medical error literature. Issues surrounding error identification are discussed. The pros and cons of mandatory reporting, voluntary reporting, and surveillance systems are addressed, as is error reporting at the clinician, hospital, and oversight group levels. Committee recommendations are made regarding the initial steps EM should take to address error. The establishment of patient safety boards at each institution is also recommended.