This systematic review examined the effectiveness of interventions to increase incident reporting by clinicians. Although incident reporting systems are universally used, they have been shown to capture only a small proportion of errors, and therefore increasing reporting rates could help improve identification of safety problems. However, this review identified only four studies of methods to increase reporting, and the authors determined that it was not possible to draw conclusions from this limited evidence base. An AHRQ WebM&M perspective discusses the complexities of capturing, prioritizing, and responding to safety events with incident reporting systems.