방법 비교

	Two-Level Game Analysis	Voting Power Index Analysis
분야	Political Science	Political Science
계열	MCDM	MCDM
기원 연도	1988	1954
창시자	Robert D. Putnam	Lloyd Shapley & Martin Shubik; John F. Banzhaf III
유형	Framework for analyzing international negotiation under domestic constraints	Cooperative game-theoretic measure of a priori voting power
원전	Putnam, R. D. (1988). Diplomacy and Domestic Politics: The Logic of Two-Level Games. International Organization, 42(3), 427-460.	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.
별칭	Two-Level Games, Putnam Two-Level Game Framework, Win-Set Analysis, Double-Edged Diplomacy	Voting Power Index, Shapley-Shubik Index, Banzhaf Power Index, A Priori Voting Power Analysis
관련	4	4
요약	Two-level game analysis is a framework introduced by Robert Putnam in 1988 for understanding how international negotiations are jointly shaped by bargaining between governments and the need to win domestic approval. A negotiator plays simultaneously at two tables: Level I, where states bargain over an agreement, and Level II, where that agreement must be ratified by domestic constituents. The key analytic device is the win-set — the set of Level I deals that could secure domestic ratification — and an agreement is possible only where the negotiating states' win-sets overlap.	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.