Relieving the Elicitation Burden of Bayesian Belief Networks

Abstract

In this paper we present a new method(EBBN) that aims at reducing the need toelicit formidable amounts of probabilities for Bayesian belief networks, by reducing thenumber of probabilities that need to be specified in the quantification phase. This methodenables the derivation of a variable’s conditional probability table (CPT) in the general case that the states of the variable areordered and the states of each of its parent nodes can be ordered with respect to the influence they exercise. EBBN requires only a limited amount of probability assessments from experts to determine a variable’s full CPT and uses piecewise linear interpolation. The number of probabilities to be assessed in this method is linear in the number of conditioning variables. EBBN’s performance wascompared with the results achieved by applying both the normal copula vine approach from Hanea & Kurowicka (2007), and by using a simple uniform distribution.