Caulier, Jean-François and Dumont, Patrick (2005): The effective number of relevant parties : how voting power improves Laakso-Taagepera’s index.
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This paper proposes a new method to evaluate the number of rel- evant parties in an assembly. The most widespread indicator of frag- mentation used in comparative politics is the ‘Eﬀective Number of Par- ties’(ENP), designed by Laakso and Taagepera (1979). Taking both the number of parties and their relative weights into account, the ENP is arguably a good parsimonious operationalization of the number of ‘relevant’ parties. This index however produces misleading results in single-party ma jority situations as it still indicates that more than one party is relevant in terms of government formation. We propose to modify the ENP formula by replacing proportions of seats by voting power measures. This improved index behaves more in line with Sar- tori’s deﬁnition of relevance, without requiring additional information in its construction.
|Item Type:||MPRA Paper|
|Original Title:||The effective number of relevant parties : how voting power improves Laakso-Taagepera’s index|
|Keywords:||Voting power indices; Eﬀective Number of Parties; Party system fragmentation; Relevance; Coalition Formation|
|Subjects:||H - Public Economics > H1 - Structure and Scope of Government > H10 - General
D - Microeconomics > D7 - Analysis of Collective Decision-Making > D71 - Social Choice ; Clubs ; Committees ; Associations
|Depositing User:||Jean-François Caulier|
|Date Deposited:||13. Oct 2009 16:09|
|Last Modified:||16. Feb 2013 10:07|
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