Alrik Thiem, "Unifying Configurational Comparative Methodology: Generalized-Set Qualitative Comparative Analysis", June 2012

Qualitative Comparative Analysis (QCA) is becoming increasingly popular with social scientists across many subfields of the discipline. More precisely, crisp-set (csQCA), fuzzy-set (fsQCA) and multi-value Qualitative Comparative Analysis (mvQCA) have emerged as distinct variants, with mvQCA still undeservedly leading a shadowy existence. This article has two objectives. First, but secondary in importance, it demonstrates that all set-data types associated with each QCA variant can be combined in a single analysis, as a result of which it also argues that the prevailing skepticism against mvQCA has no methodological foundation. Second, but primary in importance, it introduces the concept of the multi-level fuzzy set. This set-data type is at the core of generalized-set Qualitative Comparative Analysis (gsQCA), an approach which integrates the characteristic dimensions of mvQCA and fsQCA - partitioned crisp sets and graded set membership - into a single framework while retaining established truth table construction and Boolean minimization procedures. Under this novel approach, all existing variants become special cases of gsQCA.