Feedback from accidents
Risks in complex systems

Despite the precautions taken and the efforts made, industrial history shows that accidents do happen. This is the extreme difficulty of industrial management of major risks: the probability of serious accidents, of disasters, is low, but the potential consequences are very significant, in terms of harm to people (deaths, injuries), material damage and environmental damage (pollution, contamination). The scale of the effort involved, and the attention to detail, often appear out of all proportion to the reality of events that usually occur (and can be observed), whether minor or significant.

As accidents are rare events, safety policies cannot be based on statistical considerations, and safety management cannot be driven by accident rates. Safety experts and managers of high-risk installations or systems are condemned to look for signs of safety deterioration in...