At a Navy torpedo facility where I worked many years ago - a Pareto chart came out that said that the sailors doing the maintenance were the number one cause of torpedo failures found during test firings. Caused quite a stink shall we say. Careful review of the data showed that all "sailor errors" were lumped into one bin, but equipment failures were individual to the component. So we had six sailor failures, one engine failure, one CPU failure, one . . . failure - the list was a long one. Plus many of the sailor failures were related to poor procedures supplied to the facility.
Not a bad idea to have more detail for ANY failure. The responses above should help you. Blaming the operator(s) usually is a red herring - there is something behind those failures. Consider Dr. Deming's Red Beads.