“Little difficulty is experienced in correcting the mechanical hazards, but the correction of unsafe acts will remain troublesome unless there is a better understanding of the reasons or motives that permit these unsafe acts to occur. The purpose of this discussion is to point out that definite causative factors lie directly behind the occurrence of unsafe acts, that they are few in number, practicable of identification, and extremely valuable as direct clues to the selection of corrective action.”
Industrial Accident Prevention – A Scientific Approach, H. W. Heinrich, Assistant Superintendent Engineering and Inspection Division, The Travelers Insurance Company, 1941
