Interpersonal comparisons of utility and the policy paralysis problem

Several “Paretian” welfare rules are equivalent when policymakers know agents' characteristics, e.g., a policy is optimal if (a) any other policy making someone better off harms some agent, or (b) it is the maximum of some social welfare function. This paper extends these and other rules to environments where policymakers have a probability distribution over a state space of possible models. Under weak conditions, rule (a), which postulates ex ante preferences for agents, recommends some change from almost every status quo policy. Unfortunately, (a) requires a demanding form of interpersonal welfare comparability. Rule (b) labels all policies optimal if the state space obeys a weak diversity condition. Since the probabilities of states are irrelevant for this result, only a small perturbation of a model with no uncertainty generates policy paralysis. Received: 26 March 1997/Accepted: 16 November 1998