Back মাধ্যিকা মতদাতা উপপাদ্য Assamese Medianvælgere Danish Medianwählertheorem German Teorema del votante mediano Spanish قضیه رأیدهنده میانه Persian Théorème de l'électeur médian French הבוחר החציוני HE Teorema dell'elettore mediano Italian 中位投票者定理 Japanese 중위 투표자 정리 Korean
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In political science and social choice, Black's median voter theorem says that if voters and candidates are distributed along a political spectrum, any Condorcet consistent voting method will elect the candidate preferred by the median voter.[1] The median voter theorem thus shows that under a realistic model of voter behavior, Arrow's theorem does not apply, and rational choice is possible for societies. The theorem was first derived by Duncan Black in 1948,[2] and independently by Kenneth Arrow.
Similar median voter theorems exist for rules like score voting and approval voting[3][4] when voters are either strategic and informed or if voters' ratings of candidates fall linearly with ideological distance.
An immediate consequence of Black's theorem, sometimes called the Hotelling-Downs median voter theorem, is that if the conditions for Black's theorem hold, politicians who only care about winning the election will adopt the same position as the median voter.[5][6][7] However, this strategic convergence only occurs in voting systems that actually satisfy the median voter property (see below).[8][9][10]
- ^ P. Dasgupta and E. Maskin, "The fairest vote of all" (2004); "On the Robustness of Majority Rule" (2008).
- ^ Black, Duncan (1948-02-01). "On the Rationale of Group Decision-making". Journal of Political Economy. 56 (1): 23–34. doi:10.1086/256633. ISSN 0022-3808. S2CID 153953456.
- ^ Cox, Gary W. (1985). "Electoral Equilibrium under Approval Voting". American Journal of Political Science. 29 (1): 112–118. doi:10.2307/2111214. ISSN 0092-5853. JSTOR 2111214.
- ^ Myerson, Roger B.; Weber, Robert J. (March 1993). "A Theory of Voting Equilibria". American Political Science Review. 87 (1): 102–114. doi:10.2307/2938959. hdl:10419/221141. ISSN 1537-5943. JSTOR 2938959.
- ^ Holcombe, Randall G. (2006). Public Sector Economics: The Role of Government in the American Economy. Pearson Education. p. 155. ISBN 9780131450424.
- ^ Hotelling, Harold (1929). "Stability in Competition". The Economic Journal. 39 (153): 41–57. doi:10.2307/2224214. JSTOR 2224214.
- ^ Anthony Downs, "An Economic Theory of Democracy" (1957).
- ^ McGann, Anthony J.; Koetzle, William; Grofman, Bernard (2002). "How an Ideologically Concentrated Minority Can Trump a Dispersed Majority: Nonmedian Voter Results for Plurality, Run-off, and Sequential Elimination Elections". American Journal of Political Science. 46 (1): 134–147. doi:10.2307/3088418. ISSN 0092-5853.
- ^ Myerson, Roger B.; Weber, Robert J. (March 1993). "A Theory of Voting Equilibria". American Political Science Review. 87 (1): 102–114. doi:10.2307/2938959. hdl:10419/221141. ISSN 1537-5943. JSTOR 2938959.
- ^ Mussel, Johanan D.; Schlechta, Henry (2023-07-21). "Australia: No party convergence where we would most expect it". Party Politics. 30 (6): 1040–1050. doi:10.1177/13540688231189363. ISSN 1354-0688.