Group decision support systems implement Bayesian rationality

When saying that group decisions are good, one often means that they are ‘externally Bayesian’. Proposed by Madansky, the externally Bayesian criterion requires that the decisions of the group look as if they are chosen by a Bayesian individual. A process due to DeGroot satisfies this criterion. It is argued that this process corresponds to a group decision support system. This reinforces the claim that group decision support systems can improve group decision making.