Why should probabilistic risks analysis be performed?
For purposes of discussion, three reasons are proposed:
1. Regardless of our ideological view of disasters and their causes, we would all agree that preferences can be established, so that for a given frequency of occurrence (e.g., a disaster occurring once every ten years), we prefer a disaster of small impact to one of major impact. Therefore, the scale of a disaster is relevant, and we have an obligation to establish ways to measure that scale.
2. For a disaster of a specific scale, we would also prefer it to occur infrequently rather than frequently. Therefore, a disaster’s frequency of occurrence is relevant and must be taken into account in any risk assessment.
3. A high degree of uncertainty is present in virtually every risk assessment made. If we are to act rationally, this uncertainty cannot be ignored; instead, it must be acknowledged, processed, and incorporated in our assessments.