Qualitative Comparative Analysis (QCA) is an approach that enables systematically comparing qualitative case study data. The fact that QCA borrows certain elements from quantitative methods (such as the use of Boolean algebra and the quantification of conditions and outcomes) may raise questions about the qualitative character of QCA. Based on a discussion of four criteria relating to causal analysis, we argue that QCA belongs to the qualitative research tradition. Where QCA borrows characteristics from the quantitative approach, this is only for the sake of a qualitative objective: to better understand the conditions underlying a particular outcome or phenomenon.