UNCERTAINTIES IN RISK ANALYSIS - 6 LEVELS OF TREATMENT

This paper examines different levels of analytical sophistication in t he treatment of uncertainties in risk analysis, and the possibility of transfer of experience across fields of application. First, this pape r describes deterministic and probabilistic methods of treatment of ri sk and uncertainties, and the different viewpoints that shape these an alyses. Second, six different levels of treatment of uncertainty are p resented and discussed in the light of the evolution of the risk manag ement philosophy in the US. Because an in-depth treatment of uncertain ties can be complex and costly, this paper then discusses when and why a full (two-tier) uncertainty analysis is justified. In the treatment of epistemic uncertainty, an unavoidable and difficult problem is the encoding of probability distributions based on scientific evidence an d expert judgments. The last sections include a description of differe nt approaches to the aggregation of expert opinions and their use in r isk analysis, and a recent example of methodology and application (in seismic hazard analysis) that can be transferred to other domains. (C) 1996 Elsevier Science Limited