Since the 1999 Institute of Medicine report “To Err is Human: Building a Safer Health System,” hospital safety has emerged as a central issue for patients, payers, and policy makers. Based on estimates from that report, medical errors result in 44 000 to 98 000 deaths every year in the United States, making them the third leading cause of death—ahead of breast cancer, AIDS, and motor vehicle crashes.1 As a result of that report and growing scrutiny from the media and patient advocacy groups, hospitals nationwide have redoubled their efforts at improving patient safety.