Qualitative Comparative Analysis (QCA) and Related Systematic Comparative Methods

During the past two decades, a set of systematic comparative case analysis techniques has been developing at a steady pace. During the last few years especially, the main initial technique, qualitative comparative analysis (QCA), has been complemented by other related methods and techniques. The purpose of this article is to critically assess some main recent developments in this field. QCA and connected methods can be considered at two levels: as a research strategy and as a set of concrete techniques. The author first argues that such a strategy displays some decisive advantages in social science research, especially in small-and intermediate- N research designs. Second, QCA as well as three other related techniques, namely multi-value QCA (MVQCA), fuzzy sets and MSDO/MDSO, are presented in brief, and some current debates with regard to these techniques are also summarized. In the third section, the article surveys recent contributions and ongoing efforts that have provided some advances in the application of these techniques, around five key issues: case selection and model specification; measurement, dichotomization and linkage with theory; contradictions and non-observed cases; the time and process dimension; and the confrontation or combination with other methods. Finally, the article discuss the potential for further development of these methods in social science research broadly defined.