Qualitative comparative analysis and fsQCA
Compare configurations as set relations
Qualitative comparative analysis examines necessary or sufficient configurations of conditions using set relations and cross-case comparison. Crisp-set QCA uses binary membership; fuzzy-set QCA allows graded membership anchored in substantive criteria. Both rely on calibration, truth tables and logical minimisation. They are case-oriented approaches with analytic machinery, and neither is a form of conventional regression.
Use when theory suggests several combinations of conditions may produce an outcome and you have comparable cases, strong substantive knowledge and defensible calibration anchors.
Strengths
- Represents conjunctural causation and alternative pathways
- Allows asymmetric analysis of an outcome and its absence
Limitations
- Solutions are sensitive to calibration and case selection
- Limited diversity leaves many possible configurations unobserved
Know the boundary
Consistency is not a p-value, coverage is not variance explained, and a configuration alone does not prove a mechanism.