The honest opinions of a group of experts must be aggregated to determine the deserving winner of a competition. The aggregation procedure is majoritarian if, whenever a majority of experts honestly believe that a contestant is the best one, then that contestant is considered the deserving winner. The fact that an expert believes that a contestant is the best one does not necessarily imply that she wants this contestant to win as, for example, she might be biased in favor of some other contestant. Then, we have to design a mechanism that implements the deserving winner. We show that, if the aggregation procedure is majoritarian, such a mechanism exists only if the experts are totally impartial. This impossibility result is very strong as it does not depend on the equilibrium concept considered. Moreover, the result still holds if we replace majoritarianism by anonymity and other reasonable property called respect for the jury. The impossibility result is even stronger if we focus on Nash implementation: no majoritarian aggregation procedure can be Nash implemented even if the experts are totally impartial.

中文翻译：

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汇总专家意见，选出竞赛优胜者

必须汇总一组专家的诚实意见，以确定比赛的当之无愧的获胜者。如果当大多数专家真诚地相信某位参赛者是最好的时，那么该参赛者就被认为是当之无愧的获胜者，则聚合程序是多数主义的。专家认为参赛者是最好的这一事实并不一定意味着她希望该参赛者获胜，例如，她可能偏向于其他一些参赛者。然后，我们必须设计一种机制来实现应得的赢家。我们表明，如果聚合程序是多数人的，那么这种机制只有在专家完全公正的情况下才存在。这种不可能结果非常强，因为它不依赖于所考虑的均衡概念。而且，如果我们用匿名和其他称为尊重陪审团的合理财产来代替多数主义，结果仍然成立。如果我们专注于 Nash 的实施，则不可能的结果会更大：即使专家完全公正，也无法实施多数制聚合程序。