This study determined the rate with which adverse drug events (ADE) resulted in an incident report and whether differences existed among hospital personnel as to whether an incident report should or would be filed. After identifying ADEs in this single-center study, only 6% had a corresponding incident report submitted to the hospital’s quality assurance program. Quality assurance administrators, nurse leaders in quality, and staff nurses all agreed that each ADE warranted an incident report despite the findings reported. The authors conclude that voluntary reporting mechanisms will capture only a small fraction of ADEs and using incident reporting systems will likely lead to significant bias when assessing quality of care. The authors offer a plan to improve reporting systems and provide examples of how past incident reports led to changes in hospital policies and procedures.