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 the basis of all the information available to the experts. We compare two “cultures”: In the first, the experts are driven only by the public motive to choose the most desirable action. 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.