5. Discussion
Since SMAA always selects the alternative with the largest acceptability index, the probability that the SMAA model selects the same alternative as MAUT is equivalent to computing the probability that the decision maker's true preferences lie inside the largest favourable weight space. This is precisely what is computed by the largest rank-1 acceptability index. We therefore examine distributional properties of the random variable B1 ðkÞ denoting the k-th largest rank-1 acceptability index, and in particular the expected value of the largest rank-1 acceptability index E½B1 ð1Þ. Unfortunately deriving general analytical results for B1 ðkÞ is difficult, so that we first consider an artificially simple case where exact results can be obtained, and then extrapolate from these using heuristic arguments.