ON THE SOLUTION APPROACH FOR BAYESIAN MODELING OF INITIATING EVENT FREQUENCIES AND FAILURE RATES

Then is a need for plant-specific distributions of incidence and failu re rates rather than distributions from pooled data which are based on the ''common incidence rate'' assumption. The so-called superpopulati on model satisfies this need through a practically appealing approach that accounts for the variability over the population of plants. Unfor tunately, the chosen order in which the integrals with respect to the individual plant rates lambda(i) (i = 0, 1..., m) and the parameters a lpha,beta of the Gamma-population distribution are solved seems to dri ve the solution close to the common incidence rate distribution. It is shown that the solution obtained from interchanging the order and sol ving the integrals with respect to the individual plant rates by Monte Carlo simulation very quickly provides the plant specific distributio n. This differing solution behaviour may be due to the lack of uniform convergence over (alpha,beta, lambda(i) (i = 1,..., m))-space. Exampl es illustrate the difference that may be observed.