QCA is a case-based research method for capturing causal complexity. As Charles Ragin put it in The Comparative Method, QCA is a method for “comparing wholes as configurations of parts” (Ragin 1987: 84). QCA helps identify how conditions combine to produce an outcome of interest, and whether different paths can lead to the same result. The method is typically used with 20–30 cases, but it is possible to work with much larger case numbers (up to hundreds of cases). On the lower end, 12 cases can be regarded as a required minimum for useful comparisons with QCA.
Here you can find resources on QCA, how to conduct the analysis with R, training opportunities, replication materials, and video recordings. Below are also some links to QCA reviews and handbook chapters.
QCA reviews and handbook chapters
Mello, Patrick A. 2024. Uncovering Causal Complexity with Qualitative Comparative Analysis. In The Handbook of Teaching Qualitative and Mixed Research Methods: A Step-by-Step Guide for Instructors, edited by Alissa Ruth, Amber Wutich, and H. Russell Bernard. London: Routledge, 336–339.
Mello, Patrick A. 2023. Qualitative Comparative Analysis. In Routledge Handbook of Foreign Policy Analysis Methods, edited by Patrick A. Mello and Falk Ostermann. London: Routledge, 385–402.
Ide, Tobias, and Patrick A. Mello. 2022. QCA in International Relations: A Review of Strengths, Pitfalls, and Empirical Applications. International Studies Review 24 (1), 1–20.
Mello, Patrick A. 2017. Qualitative Comparative Analysis and the Study of Non-State Actors. In Researching Non-State Actors in International Security: Theory & Practice, edited by Andreas Kruck and Andrea Schneiker. London: Routledge, 123–142.