Probative blindness: how safety activity can fail to update beliefs about safety

Accidents are preceded by a period where, in hindsight, there was an opportunity to recognise and prevent the impending disaster. Various theories have attempted to describe and explain why warning signs are ignored. This paper examines the specific role of safety analysis as a warning mechanism. Depending on the context of the analysis, and the selection of activities, safety analysis may only serve to provide assurance of safety, even when such assurance is unwarranted. A better understanding of false assurance prior to accidents will allow for more appropriate selection, performance and interpretation of safety analysis methods and results.