Little, Kevin (1989, ASQC) Joiner Associates Inc., Madison, WI
All large industrial enterprises (and many small ones, too) have had to gather and submit data on accidents according to the requirements of the Occupational Health and Safety Act of 1970. These data often show that reportable accidents are in statistical control when plotted on a suitable control chart. What are the implications for managers when such accidents exhibit stability in the control chart sense? This simple statistical perspective provides a basis for this paper. We can analyze both accident data and the ways organizations work to improve safety to illustrate several principles of modern management. Such an analysis when conducted within an organization can serve as a case-study for in-house process improvement training for managers.
I review basic models of accidents from the statistical literature. Starting from the Poisson model and a basic generalization proposed first by M. Greenwood and G.U. Yule in 1920, I discuss what assumptions these models make about the circumstances of accidents. I also review the basic understanding of accidents from the industrial engineering literature and relate the engineering models to modern management principles, starting with H.W. Heinrich's domino model, first proposed in 1931.I summarize basic statistical and engineering approaches to accidents and safety. I relate these approaches to modern management principles and show how these approaches fit into the modern view of an organization as a system that can be improved. I outline how to build a case study for internal training, using an organization's safety data.