ABSTRACT
Probabilistic scenario analysis (PSA) combines the power of scenario structuring and probabilistic tools to produce a useful bundle of tools called PSAs. Most probabilistic risk assessments are likely to be some form of PSA. Monolithic, deterministic, and probabilistic scenarios are each defined. Scenario comparisons are useful for evaluating the potential impacts of risk management options. Before and after, without and with condition, and gap analysis are three methods used to compare scenarios. Influence diagrams and tree models are presented as handy tools for structuring scenarios, especially in a spreadsheet environment. Once a probabilistic method, like the Monte Carlo process, is added to the scenario tools useful models can be constructed for a wide variety of risk assessment situations.
