השוואת שיטות

	Voting Power Index Analysis	Veto Player Analysis
תחום	Political Science	Political Science
משפחה	MCDM	MCDM
שנת המקור	1954	1995
הוגה השיטה	Lloyd Shapley & Martin Shubik; John F. Banzhaf III	George Tsebelis
סוג	Cooperative game-theoretic measure of a priori voting power	Comparative institutional analysis framework
מקור מכונן	Shapley, L. S., & Shubik, M. (1954). A Method for Evaluating the Distribution of Power in a Committee System. American Political Science Review, 48(3), 787-792.	Tsebelis, G. (2002). Veto Players: How Political Institutions Work. Princeton University Press. ISBN: 9780691091891
כינויים	Voting Power Index, Shapley-Shubik Index, Banzhaf Power Index, A Priori Voting Power Analysis	Veto Players Theory, Veto Points Analysis, Tsebelis Veto Player Framework, Policy Stability Analysis
קשורות	4	4
תקציר	Voting power index analysis measures the a priori capacity of each member of a weighted voting body to influence collective decisions, defined as the probability that the member is pivotal — that their vote turns a losing coalition into a winning one. The two canonical indices are the Shapley-Shubik index, introduced by Lloyd Shapley and Martin Shubik in 1954 as a specialization of the Shapley value to simple voting games, and the Banzhaf index, formalized by John Banzhaf in 1965. Both reveal that a player's share of power generally differs sharply from its share of votes.	Veto player analysis is a spatial-institutional framework, developed by George Tsebelis in his 1995 article and 2002 book, for predicting the capacity of a political system to change policy. A veto player is any individual or collective actor whose agreement is required to alter the status quo. The theory shows that the potential for policy change shrinks as the number of veto players grows, as the ideological distance between them widens, and as their internal cohesion increases — three structural variables that together determine a system's policy stability independently of constitutional labels such as presidentialism or parliamentarism.