Qualified Majorities and Expert Choice

  • Adiel Teixeira de AlmeidaEmail author
  • Danielle Costa Morais
  • Hannu Nurmi
Part of the Advances in Group Decision and Negotiation book series (AGDN, volume 9)


What if the decision makers have different degrees of expertise and the aim is to maximize the probability of a correct decision? (The first three sub-sections are largely based on Nurmi, Voting procedures under uncertainty. Springer, Berlin-Heidelberg, pp 49–59, 2002) This possibility has been considered for a long time. We shall describe the main results in this field of inquiry where the degrees of competence play a crucial role. We begin with a classic result that is based on the assumption that the individual decision competences are equal and representable by the probability that the decision made by the individual is correct. The issue of where the competence probability comes from is left open. We also discuss epistemic paradoxes, i.e. peculiarities encountered when aggregating premises of an argument separately from the conclusions.


  1. Ben-Yashar, R., & Paroush, J. (2000). A nonasymptotic Condorcet jury theorem. Social Choice and Welfare, 17, 189–199.MathSciNetCrossRefGoogle Scholar
  2. Berg, S. (1993). Condorcet’s Jury Theorem, dependency among voters. Social Choice and Welfare, 10, 87–96.Google Scholar
  3. Boland, J. (1989). Majority systems and the Condorcet Jury Theorem. The Statistician, 38, 181–189.Google Scholar
  4. Boland, J., Proschan, F., & Tong, Y. (1989). Modelling dependence in simple and indirect majority systems. Journal of Applied Probability, 26, 81–88.MathSciNetCrossRefGoogle Scholar
  5. Bovens, L., & Rabinowicz, W. (2006). Democratic answers to complex questions—An epistemic perspective. Synthese, 150, 131–153.MathSciNetCrossRefGoogle Scholar
  6. Dahl, R. (1970). After the revolution. New Haven: Yale University Press.Google Scholar
  7. Dietrich, F., & List, C. (2013). A reason-based theory of rational choice. Nous, 47, 104–134.MathSciNetCrossRefGoogle Scholar
  8. Grofman, B., Owen, G., & Feld, S. (1983). Thirteen theorems in search of the truth. Theory and Decision, 15, 261–278.MathSciNetCrossRefGoogle Scholar
  9. Kornhauser, L. (1992). Modelling collegial courts. II. Legal doctrine. Journal of Law, Economics and Organization, 8, 441–470.Google Scholar
  10. Kornhauser, L., & Sager, L. (1986). Unpacking the court. Yale Law Journal, 96, 82–117.Google Scholar
  11. List, C. (2011). The logical space of democracy. Philosophy and Public Affairs, 39, 262–297.CrossRefGoogle Scholar
  12. List, C. (2012). The theory of judgment aggregation: An introductory review. Synthese, 187, 179–207.MathSciNetCrossRefGoogle Scholar
  13. List, C., & Pettit, P. (2002). Aggregating sets of judgments: An impossibility result. Economics and Philosophy, 18, 89–110.CrossRefGoogle Scholar
  14. McLean, I., & Urken, A. (Eds.). (1995). Classics of social choice. Ann Arbor: The University of Michigan Press.Google Scholar
  15. Miller, N. R. (1986). Information, electorates, and democracy: Some extensions and interpretations of the Condorcet Jury Theorem. In B. Grofman & G. Owen (Eds.), Information pooling and group decision making. Greenwich, CT: JAI Press.Google Scholar
  16. Nitzan, S., & Paroush, J. (1982). Optimal decision rules in uncertain dichotomous choice situations. International Economic Review, 23, 289–297.Google Scholar
  17. Nurmi, H. (2002). Voting procedures under uncertainty. Berlin-Heidelberg: Springer.Google Scholar
  18. Owen, G., Grofman, B., & Feld, S. L. (1989). Proving a distribution-free generalization of the Condorcet Jury Theorem. Mathematical Social Sciences, 17(1), 1–16.Google Scholar
  19. Pettit, P. (2001). Deliberative democracy and discursive dilemma. Philosophical Issues,11, 268–299.Google Scholar
  20. Shapley, L., & Grofman, B. (1984). Optimizing group judgmental accuracy in the presence of uncertainties. Public Choice, 43, 329–343.CrossRefGoogle Scholar
  21. Vacca, R. (1921). Opinioni individuali e deliberazione collettive. Rivista Internazionale di Filosofia del Diritto, 52–59.Google Scholar

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Universidade Federal de Pernambuco (UFPE)RecifeBrazil
  2. 2.University of TurkuTurkuFinland

Personalised recommendations