A modeling framework for exposing risks in complex systems

This article introduces and develops a modeling framework for exposing risk s in the form of human errors and adverse consequences in high-risk systems . The modeling framework is based on two components: a two-dimensional theo ry of accidents in systems developed by Perrow in 1984, and the concept of multiple system perspectives. The theory of accidents differentiates system s on the basis of two sets of attributes. One set characterizes the degree to which systems are interactively complex; the other emphasizes the extent to which systems are tightly coupled. The concept of multiple perspectives provides alternative descriptions of the entire system that serve to enhan ce insight into system processes. The usefulness of these two model compone nts derives from a modeling framework that cross-links them, enabling a var iety of work contexts to be exposed and understood that would otherwise be very difficult or impossible to identify. The model components and the mode ling framework are illustrated in the case of a large and comprehensive tra uma care system. In addition to its general utility in the area of risk ana lysis, this methodology may be valuable in applications of current methods of human and system reliability analysis in complex and continually evolvin g highrisk systems.