From probabilistics to determinism: an essay on risk assessment and decisionmaking in sociotechnical systems

Probabilistic analysis is the usual starting point for sociotechnical risk assessments aimed at deciding whether or not a particular risk is acceptable. However, the available probabilistic evidence is usually insufficient as a basis for such decisions, and so the assessment has to be supplemented by a judgemental process of a more deterministic nature. This concluding phase in decisionmaking is essentially non-rational, involving amongst other things intuition and image formation. The conceptual incompatibility between the final stage in risk assessment and the preceding probabilistic analysis means that it is not possible to arrive at an overall quantitative account of the decisionmaking process.