S. Chhibber et G. Apostolakis, SOME APPROXIMATIONS USEFUL TO THE USE OF DEPENDENT INFORMATION-SOURCES, Reliability engineering & systems safety, 42(1), 1993, pp. 67-86
Citations number
20
Categorie Soggetti
Engineering,"Operatione Research & Management Science
Expert judgments have been frequently utilized in probabilistic risk a
ssessments. The aggregation methods used have often been very simplist
ic and have ignored the critical issues of incorporating experts' bias
es and inter-expert dependence. On the other hand, theoretical methods
available address some of these issues, but suffer from the fact that
the input requirements are too demanding. This paper provides practic
al guidance on the use of the versatile Bayesian expert judgment aggre
gation model. Guidance is provided by conducting a sensitivity analysi
s of the experts' weights and posterior standard deviation on the para
meters of the Bayesian aggregation model. Experts' weights and posteri
or standard deviation are most sensitive to experts' standard deviatio
ns and are not as sensitive to inter-expert dependence. Experts' locat
ion biases influence the posterior mean, but not the posterior varianc
e and weights. The results obtained are also applicable to the more co
mmonly used judgment aggregation procedures, such as simple geometric
averaging, because the Bayesian aggregation method encompasses these s
imple techniques. The results are illustrated with the help of an exam
ple and suggest that the uncertainty is underestimated if expert biase
s are ignored.