Modelling Under Risk and Uncertainty: An Introduction to Statistical, Phenomenological and Computational Methods

1 The Scope of Risk and Uncertainty Considered

Risk and uncertainty are closely linked concepts and distinguishing them is not free from controversy. Facing up to the hard task of defining these two concepts precisely, some preliminary comments will be made at this stage. Uncertainty is the subject of long-standing epistemological interest as it stands with a fundamental connection both to any type of modelling activity and the scientific consideration of risk. The former relates to the fact that any modelling endeavour brings with it a more or less explicit consideration of the uncertain deviation of the model from empiric evidence. The latter focuses on the detrimental (or beneficial) consequences of uncertain events in terms of some given stakes, assets or vulnerability of interest for the decision-maker. Risk and uncertainty analysis prove to be so connected in application that the precise delimitation between the practical meanings of the two terms will not appear to be central with regard to modelling: it depends essentially on the definition of the underlying system or on the terminological habits of the field under consideration. The system considered generally includes the undesired consequences or performance indicators of a given industrial facility or environmental asset in a fully-fledged risk assessment, while it may be limited to a technical or modelling sub-part seen from a narrower perspective when talking about uncertainty or sensitivity analysis. Chapter 1 reviews ...