A DECISION-ORIENTED MEASURE OF UNCERTAINTY IMPORTANCE FOR USE IN PSA

For the interpretation of the results of probabilistic risk assessment s it is important to have measures which identify the basic events tha t contribute most to the frequency of the top event but also to identi fy basic events that are the main contributors to the uncertainty in t his frequency. Both types of measures, often called Importance Measure and Measure of Uncertainty Importance, respectively, have been the su bject of interest for many researchers in the reliability field. The m ost frequent mode of uncertainty analysis in connection with probabili stic risk assessment has been to propagate the uncertainty of all mode l parameters up to an uncertainty distribution for the top event frequ ency. Various uncertainty importance measures have been proposed in or der to point out the parameters that in some sense are the main contri butors to the top event distribution. The new measure of uncertainty i mportance suggested here goes a step further in that it has been devel oped within a decision theory framework, thereby providing an indicati on of on what basic event it would be most valuable, from the decision -making point of view, to procure more information. (C) 1997 Elsevier Science Limited.