A social scientific introduction to set theory and Qualitative Comparative Analysis (QCA)

Use of set theory and the set-theoretic method Qualitative Comparative Analysis (QCA) has increased considerably in the social sciences in recent years. This growth has in turn triggered a fruitful and at times intense debate in some of the most prestigious international journals. At the same time, there is limited methodological literature and scholarly debate in Norwegian about this burgeoning field, and set theory and QCA is only taught occasionally at Norwegian universities. This is unfortunate considering that set theory offers an alternative and increasingly recognized way of understanding and investigating causal relationships in the social world vis-a-vis experimental quantitative research designs. Thus, Norwegian social scientists and students risk missing out on methodological perspectives and tools that may contribute to a stronger scientific anchoring of qualitative methods in the social sciences. The purpose of this article is therefore to introduce set theory and QCA to a Norwegian audience. In addition to describing key set-theoretic principles, the article explains when QCA may be suitable as a research strategy, and then gives a step-by-step guide to QCA as a method. The aim is that this introduction will provide sufficient knowledge for anyone interested in conducting a QCA study of their own. Finally, the article discusses three known objections to QCA.