The Human Factors Analysis and Classification System (HFACS) identifies the human causes of an accident and offers tools for analysis as a way to plan preventive training. It was developed by Dr. Scott Shappell of the Civil Aviation Medical Institute and Dr. Doug Wiegmann of the University of Illinois at Urbana-Campaign in response to a trend that showed some form of human error was a primary causal factor in 80% of all flight accidents in the Navy and Marine Corps.