Publication detail

Fair Voting Majorities in Proportional Representation

Author(s): † prof. RNDr. Ing. František Turnovec CSc.,
Type: Article in collection
Year: 2011
Number: 0
ISSN / ISBN: 978-80-7431-059-1
Published in: Mathematical Methods in Economics 2011, part II (listed in the Thomson Reuters ISI Index to Social Sciences & Humanities Proceedings (ISSHP) and the Thomson Reuters ISI Index to Social Sciences & Humanities Proceedings (ISSHP/ISI Pr
Publishing place: University of Economics, Prague, Faculty of Informatics and Statistics
Keywords: fair majority, power indices, quota interval of stable power, simple weighted committe, voting power
JEL codes: C71, D72, H77
Suggested Citation: Turnovec F. (2011), Fair Voting Majorities in Proportional Representation. In: Dlouhy M. and V. Skocdopolova (eds), Mathematical Methods in Economics 2011, part II, University of Economics, Prague, pp. 727-732.
Grants: GACR 402/09/1066: Political Economy of Voting Behavior: Rational Voter Theory and Models of Strategic Voting
Abstract: In parliaments elected by proportional systems the seats are allocated to the political parties roughly proportionally to the shares of votes for the party lists obtained in elections. Assuming that members of the parliament representing the same party are voting together, it has sense to require that distribution of the influence of the parties in parliamentary decision making is oportional to the distribution of seats. There exist measures (so called voting power indices) reflecting an ability of each party to influence outcome of voting. Power indices are functions of distribution of seats and voting quota (where voting quota means a minimal number of votes required to pass a proposal). By a fair voting rule we call such a quota that leads to proportionality of influence to relative representation. Usually simple majority is not a fair voting rule. That is the reason why so called qualified or constitutional majority is being used in voting about important issues requiring higher level of consensus. Qualified majority is usually fixed (60% or 66.67%) independently on the structure of political representation. In the paper we use game-theoretical model of voting to find a quota that defines the fair voting rule as a function of the structure of political representation. Such a quota we call a fair majority. Fair majorities can differ for different structures of the parliament. Concept of a fair majority is illustrated on the data for the Lower House of the Czech Parliament elected in 2010.
Downloadable: Mathematical Methods in Economics 2011, part II, 727-732.

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