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Committee decisions: Optimality and Equilibrium

Author

Listed:
  • Jean-François Laslier

    (X-DEP-ECO - Département d'Économie de l'École Polytechnique - X - École polytechnique)

  • Jörgen Weibull

    (X-DEP-ECO - Département d'Économie de l'École Polytechnique - X - École polytechnique, SSE - Department of Economics - SSE - Stockholm School of Economics)

Abstract

We consider a group or committee that faces a binary decision under uncertainty. Each member holds some private information. Members agree which decision should be taken in each state of nature, had this been known, but they may attach different values to the two types of mistake that may occur. Most voting rules have a plethora of uninformative equilibria, and informative voting may be incompatible with equilibrium. We analyze an anonymous randomized majority rule that has a unique equilibrium. This equilibrium is strict, votes are informative, and the equilibrium implements the optimal decision with probability one in the limit as the committee size goes to infinity. We show that this also holds for the usual majority rule under certain perturbations of the behavioral assumptions: (i) a slight preference for voting according to one's conviction, and (ii) transparency and a slight preference for esteem. We also show that a slight probability for voting mistakes strengthens the incentive for informative voting.

Suggested Citation

  • Jean-François Laslier & Jörgen Weibull, 2008. "Committee decisions: Optimality and Equilibrium," Working Papers halshs-00121741, HAL.
  • Handle: RePEc:hal:wpaper:halshs-00121741
    Note: View the original document on HAL open archive server: https://hal.science/halshs-00121741v3
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    References listed on IDEAS

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    Cited by:

    1. Elchanan Mossel & Allan Sly & Omer Tamuz, 2015. "Strategic Learning and the Topology of Social Networks," Econometrica, Econometric Society, vol. 83(5), pages 1755-1794, September.
    2. Bezalel Peleg & Shmuel Zamir, 2009. "On Bayesian-Nash Equilibria Satisfying the Condorcet Jury Theorem: The Dependent Case," Discussion Paper Series dp527, The Federmann Center for the Study of Rationality, the Hebrew University, Jerusalem.
    3. Tovey, Craig A., 2010. "The instability of instability of centered distributions," Mathematical Social Sciences, Elsevier, vol. 59(1), pages 53-73, January.
    4. Bezalel Peleg & Shmuel Zamir, 2008. "Condorcet Jury Theorem: The Dependent Case," Levine's Working Paper Archive 122247000000002115, David K. Levine.

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    More about this item

    Keywords

    Voting; Condorcet; committee; judgement aggregation.; judgement aggregation;
    All these keywords.

    JEL classification:

    • D71 - Microeconomics - - Analysis of Collective Decision-Making - - - Social Choice; Clubs; Committees; Associations
    • D72 - Microeconomics - - Analysis of Collective Decision-Making - - - Political Processes: Rent-seeking, Lobbying, Elections, Legislatures, and Voting Behavior

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