手法を比較

	Qualitative Comparative Analysis	Most Similar Systems Design
分野	Political Science	Political Science
系統	Process / pipeline	Process / pipeline
提唱年	1987	1970
提唱者	Charles C. Ragin	John Stuart Mill (method of difference); Przeworski & Teune (systems framing)
種類	Set-theoretic, configurational comparative method	Small-N comparative case-selection design
原典	Ragin, C. C. (1987). The Comparative Method: Moving Beyond Qualitative and Quantitative Strategies. Berkeley: University of California Press. ISBN: 9780520058347	Przeworski, A., & Teune, H. (1970). The Logic of Comparative Social Inquiry. New York: Wiley-Interscience. ISBN: 9780471701422
別名	QCA, csQCA, fsQCA, Configurational comparative method	MSSD, Most similar cases design, Mill's method of difference, Comparable cases strategy
関連	3	3
概要	Qualitative Comparative Analysis (QCA) is a set-theoretic, configurational method that identifies which combinations of conditions are necessary or sufficient for an outcome across a set of cases. Developed by Charles Ragin, it treats each case as a configuration of set memberships, builds a truth table of all logically possible combinations, and uses Boolean algebra to minimize them into the simplest expressions that account for the outcome. It bridges qualitative case knowledge and cross-case generalization, embracing causal complexity through conjunctural causation, equifinality, and asymmetry.	The most similar systems design (MSSD) is a small-N comparative strategy that selects cases as alike as possible on many background characteristics but differing on the outcome of interest. By matching cases so that most potential confounders are held roughly constant, the design isolates the few factors that vary alongside the outcome as the candidate causes. Rooted in John Stuart Mill's method of difference and named by Przeworski and Teune, it is a cornerstone of comparative politics for drawing causal inferences from a handful of countries or cases.