Abstract
Large, complex organizations implement a range of policies and procedures to protect against risk. Sometimes, however, catastrophic accidents occur, such as with the Challenger and Columbia shuttles. “Procedural drift” has been suggested as a source of such accidents (Rasmussen, Pejtersen, & Goldstein, 1994), a process whereby procedures gradually shift, based on operating experience, until an extreme situation causes the shifted procedures to fail. Brief case studies were conducted of the shuttle accidents to explore and refine this hypothesis and to develop methods for investigating it systematically, including a “knowledge map” method, initially described by Lintern (2003). A knowledge map is a theoretically-driven variant of a work domain analysis (Rasmussen et. al., 1994), which incorporates procedural task analysis and organizational controls to analyze the overarching goal of the system. This enables visualization of how procedures occur within the organization, describing collaborations, decisions, and management procedures. Secondary goals are achieved through tasks, and tasks are further broken down into sub-tasks to describe how the system, at its procedural level, acts within the global constraints of the system. Since the knowledge map method does not generate runnable models, a system dynamics model was also developed to model the processes and dynamics of procedural drift, particularly as it affects safety. This combination of methods shows considerable promise in analyzing the shuttle accidents in particular and procedural drift and organizational risk in general.
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