Inferring Causal Complexity

In The Comparative Method, Ragin (1987) outlined a procedure of Boolean causal reasoning operating on pure coincidence data that has since become widely known as qualitative comparative analysis (QCA) among social scientists. QCA-including its recent forms as presented in Ragin (2000, 2008)-is designed to analyze causal structures featuring no more than one effect and a possibly complex configuration of mutually independent direct causes of that effect. This article presents a procedure of causal reasoning that operates on the same type of empirical data as QCA and that implements Boolean techniques related to the ones resorted to by QCA. Yet in contrast to QCA, the procedure introduced here successfully identifies structures involving both multiple effects and mutually dependent causes. In this sense, this article generalizes QCA.