Motives and implementation: On the design of mechanisms to elicit opinions

A number of experts receive noisy signals regarding a desirable public decision. The public target is to make the best possible decision on thr basis of all the information held by the experts. We compare two "cultures." Tn one, all experts are driven only by the public motive to increase the probability that the desirable action will be taken. In the second, each expert is also driven by a private motive: to have his recommendation accepted. We show that in the First culture, every mechanism will have an equilibrium which does not achieve the public target, whereas the second culture gives rise to a mechanism whose unique equilibrium outcome does achieve the public target. (C) 1998 Academic Press.