Optimal Decision Rules for the Discursive Dilemma

Abstract

We consider the classical problem in truth-tracking judgment aggregation of a conjunctive agenda with two premisses and one conclusion. We study this problem from the point of view of finding the best decision rule according to a quantitative criterion, under very mild restrictions on the set of admissible rules. The members of the deciding committee are assumed to have a certain probability to assess correctly the truth or falsity of the premisses, and the best rule is the one that minimises a combination of the probabilities of false positives and false negatives on the conclusion.