In 1999 the Committee on Quality of Health Care in America, Institute of Medicine (IOM) conducted two large studies, one in Colorado and Utah, the other in New York. Based on the Colorado and Utah findings, it was determined that at least 44,000 patients in hospitals die from medical errors each year. Based on the New York study, it was determined that the number could be closer to 98,000.These numbers were relative to the 1997 patient admissions in all U.S. hospitals which were over 33.6 million.

The IOM reported that every year at least one million medication errors of a serious nature occur in hospitals alone. Medical errors are so prevalent that one in five Americans admit they or family members have been a victim of a medical error either by a doctor or in a hospital.