The Impossibility of Bayesian Group Decision Making with Separate Aggregation of Beliefs and Values

2Bayesian paradigm. Following it, probability assessments and utility functions are defined independently. It seems reasonable to suggest that groups adopt a similar approach.3 That is, the group should deal separately with the two areas of potential disagreement. By some prescribed procedure, the group aggregates the individual probability assessments into a group probability assessment. Similarly, a group utility function is constructed by aggregating individual utility functions. The group probability assessment and utility function are multiplied in the usual manner to give expected utilities. The action offering the highest expected utility is chosen.4 Most real world decision processes, we recognize, make less than conscientious attempts to separate beliefs from values, either in debate or at time of decision.5