Beyond Normal Accidents and High Reliability Organizations: The Need for an Alternative Approach to Safety in Complex Systems

Abstract

Organizational factors play a role in almost all accidents and are a critical part of understanding and preventing them. Two prominent sociological schools of thought have addressed the organizational aspects of safety: Normal Accident Theory (NAT) [15, 23] and High Reliability Organizations (HRO) [7, 8, 19, 20, 22, 25, 26, 27]. In this paper, we argue that the conclusions of HRO researchers (labeled HRO in the rest of this paper) are limited in their applicability and usefulness for complex, high-risk systems. HRO oversimplifies the problems faced by engineers and organizations building safety-critical systems and following some of the recommendations could lead to accidents. NAT, on the other hand, does recognize the difficulties involved but is unnecessarily pessimistic about the possibility of effectively dealing with them. An alternative systems approach to safety in described, which avoids the limitations of NAT and HRO. While this paper uses the Space Shuttle, particularly the Columbia accident, as the primary example, the conclusions apply to most high-tech, complex systems.