Hospital incident reporting systems are ubiquitous, but many events remain unreported. This pre-post study sought to determine the impact of a reengineered medication error reporting approach. Researchers implemented a Web-based electronic medication error reporting system in concert with a novel work process in which clinical managers perform the first review of the report. The intervention led to increased error reporting, with the majority of errors being near-misses. This finding suggests that under-reporting of medication errors via standard incident reporting mechanisms can be addressed using human factors engineering approaches, which apply to and enhance both the error reporting tool and clinicians' workflow. A past AHRQ WebM&M perspective discusses how human factors engineering can be used to uncover problems with device design and work processes.