This qualitative study assessed how residents report or acknowledge the occurrence of medical errors. Investigators interviewed 26 residents to discuss 73 specific cases involving error. Results suggested that less than half of the errors were formally noted in the medical record, while only one-third received discussion but also were not documented. The authors conclude that health care providers represent a critical information source to better understand the systems that lead to errors. Both education about and discussion of medical errors should produce greater insight through increased acknowledgment of errors when they occur.