Measuring Voting Power: The Paradox of New Members vs. the Null Player Axiom

  • László Á. Kóczy
Part of the Studies in Computational Intelligence book series (SCI, volume 243)


Qualified majority voting is used when decisions are made by voters of different sizes. In such situations the voters’ influence on decision making is far from obvious; power measures are used for an indication of the decision making ability. Several power measures have been proposed and characterised by simple axioms to help the choice between them. Unfortunately the power measures also feature a number of so-called paradoxes of voting power. In this paper we show that the Paradox of New Members follows from the Null Player Axiom. As a corollary of this result it follows that there does not exist a power measure that satisfies the axiom, while not exhibiting the Paradox.


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© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  • László Á. Kóczy
    • 1
  1. 1.Keleti Faculty of Economics, Budapest Tech., Department of EconomicsMaastricht UniversityBudapest

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