Confronting Theories Based on Necessary Relations: Making the Best of QCA Possibilities

AbstractCurrent standard practices put sufficiency at the core of Qualitative Comparative Analysis (QCA), while the analysis of necessity is limited to the test for necessary conditions. Here, we argue that the possibilities of QCA in the latter domain are much greater. In particular, it can be used to empirically confront theories centered on necessary relations and that involved various conditions. A new operation, labeled the "systematic necessity assessment," is therefore introduced. To show its added value, a published QCA study that confronts theories centered on necessary relations but using the regular minimization is replicated.(ProQuest: ... denotes formulae omitted.)IntroductionMore than 20 years ago, Most and Starr (1989), followed by Goertz and Starr (2003), called upon their peers to be more rigorous in the analysis of necessary conditions, all types of research design considered. They argued that despite the existence in political science of many theories based on necessary relations, researchers rarely use appropriate techniques to empirically test them. The reason for this gap, lies in the absence of an adequate tool-kit. With the exception of the quantitative models developed by Braumoeller and Goertz (2000) and by Clark, Gilligan, and Golder (2006), mainstream quantitative methods unravel symmetric causal relations that cannot grasp the particularity of necessary relations. Qualitative Comparative Analysis (QCA) in contrast, Goertz and Starr argued (2003, 13), could potentially overcome these shortcomings and complete the tool-kit in this respect, thanks to its set-theoretic logic.For many years, however, QCA developers did not seem to have attached great importance to this possibility. As a matter of fact, the development of the method was mainly concerned with the other type of asymmetrical causal relation, namely sufficiency. Today, despite the recent rise of specific operations to evaluate the necessary character of individual conditions, the analysis of necessary relations is still falling behind. To fill this gap, this article proposes a new operation, labeled as the "systematic necessity assessment"1 that fully exploits QCA's possibilities in this domain, and that produces useful answers to research questions addressing competing theories centered on necessary relations. In particular, it allows identifying how some of these conditions are combined, sometimes in unexpected ways, to form SUIN conditions (sufficient but unnecessary part of a configuration that is insufficient but necessary for the outcome). The article is structured in four parts, first, the current standard practices concerning necessity in QCA are described; second, in mirroring the minimization, the systematic necessity assessment is presented together with the central concepts of SUIN conditions; third, a stepwise procedure to perform this operation is described in a didactical way; and finally, a published QCA analysis is replicated to show its added value.Necessity and QCAThanks to its set-theoretic feature, QCA is well-equipped for the analysis of necessary conditions. One of its strengths indeed resides in its ability to deal with causal complexity and more particularly with asymmetrical causality such as necessary relations. Formally speaking, necessity applies to conditions that are present in every case disclosing the outcome. Yet, and this is where the asymmetry appears, it does not say anything for the cases not disclosing it. Those cases are thus irrelevant for the necessary relation as the outcome may be present or absent without hindering the necessity feature of the conditions. Put in terms of set-theoretic logic, it amounts to saying that the outcome is a subset of the necessary condition (Ragin 2008, 13-28).Nevertheless, despite QCA's ability to deal with asymmetrical causal relations, necessity did not occupy a central position in Ragin's seminal work introducing csQCA (Ragin 1987). …