手法を比較

	Coalition Formation Analysis	Government Formation Model
分野	Political Economy	Political Economy
系統	MCDM	MCDM
提唱年	1962	1989
提唱者	William Riker; Michael Laver & Norman Schofield	David Baron & John Ferejohn; David Austen-Smith & Jeffrey Banks
種類	Formal theory of coalition selection	Non-cooperative bargaining model of government formation
原典	Riker, W. H. (1962). The Theory of Political Coalitions. Yale University Press. ISBN: 9780300001754	Baron, D. P., & Ferejohn, J. A. (1989). Bargaining in Legislatures. American Political Science Review, 83(4), 1181-1206.
別名	Minimal Winning Coalition Theory, Riker Size Principle, Coalition Theory, Government Coalition Analysis	Legislative Bargaining Model, Baron-Ferejohn Model, Formateur Model, Portfolio Allocation Model
関連	4	4
概要	Coalition formation analysis is the formal study of which subset of parties will combine to form a governing or decision-making coalition when no single party commands a majority. William Riker's 1962 The Theory of Political Coalitions supplied the foundational logic: under pure office-seeking, rational politicians form minimal winning coalitions and, by the size principle, the smallest winning coalition possible, so that the spoils of office are divided among as few partners as necessary. Michael Laver and Norman Schofield's 1990 Multiparty Government enriched this with policy-seeking motives, showing that coalitions also tend to be ideologically connected. The framework predicts coalition membership from seat shares and party positions.	The government formation model is a non-cooperative bargaining theory explaining how a cabinet and the division of its portfolios emerge when no party holds a majority. In the canonical Baron-Ferejohn (1989) framework, a head of state or chance mechanism recognizes one party as formateur with a probability often proportional to its seat share; the formateur proposes a government and an allocation of the spoils of office, and the proposal takes effect only if a legislative majority accepts. Austen-Smith and Banks (1988) embed this in an electoral and coalition setting. The model's signature result is a proposer (formateur) advantage: the party that gets to propose secures a disproportionate share of portfolios.