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Aggregating experts’ opinions to select the winner of a competition

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  • Pablo Amorós

    (Universidad de Málaga)

Abstract

The opinions of a group of experts must be aggregated to determine the deserving winner of a competition. The procedure of aggregation is majoritarian if, whenever a majority of experts honestly believe that a contestant is the best, the given contestant is considered the deserving winner. The fact that an expert believes that a contestant is the best does not necessarily imply that he/she wants this contestant to win as, for example, he/she might be biased in favor of another contestant. A mechanism is thus needed to provide the appropriate incentives to the experts so that, in equilibrium, they choose 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 concept of ordinal equilibrium. Moreover, it holds even if we replace majoritarianism by unanimity (whenever a contestant is honestly viewed as best by all experts, then that contestant is considered the deserving winner) and anonymity (changing the names of the experts with each opinion would not change the deserving winner).

Suggested Citation

  • Pablo Amorós, 2020. "Aggregating experts’ opinions to select the winner of a competition," International Journal of Game Theory, Springer;Game Theory Society, vol. 49(3), pages 833-849, September.
    • Handle: RePEc:spr:jogath:v:49:y:2020:i:3:d:10.1007_s00182-020-00712-6
    DOI: 10.1007/s00182-020-00712-6
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    References listed on IDEAS

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    More about this item

    Keywords

    Mechanism design; Social choice; Aggregation of experts’ opinions; Jury;
    All these keywords.

    JEL classification:

    • C72 - Mathematical and Quantitative Methods - - Game Theory and Bargaining Theory - - - Noncooperative Games
    • D71 - Microeconomics - - Analysis of Collective Decision-Making - - - Social Choice; Clubs; Committees; Associations
    • D78 - Microeconomics - - Analysis of Collective Decision-Making - - - Positive Analysis of Policy Formulation and Implementation

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