Set-Theoretic Multimethod Research

Set-theoretic multimethod research (SMMR) integrates the cross-case logic of Qualitative Comparative Analysis with the within-case logic of process tracing. After QCA identifies the combinations of conditions that are necessary or sufficient for an outcome, SMMR uses the resulting solution terms to classify cases — typical, deviant, individually irrelevant — and to select cases for in-depth process tracing. Codified by Carsten Schneider and Ingo Rohlfing, it grounds the choice of cases and the search for mechanisms in set theory, so cross-case and within-case inference reinforce one another within a single, coherent framework.