Ch. 4: Statistical research designs for causal inference

In Chapter 3 we have discussed the different ways in which the social sciences conceptualize causation and we have argued that there is no single way in which causal relationships can be defined and analyzed empirically. In this chapter, we focus on a specific set of approaches to constructing research designs for causal analysis, namely, one based on the potential outcomes framework developed in statistics. As discussed in Chapter 3, this perspective is both probabilistic and counterfactual. It is probabilistic because it does not assume that the presence of a given cause leads invariably to a given effect, while it is counterfactual because it involves the comparison of actual configurations with hypothetical alternatives that are not observed in reality. In essence, this approach underscores the necessity to rely on comparable groups in order to achieve valid causal inferences. An important implication is that the design of a study is of paramount importance. The way in which the data are produced is the critical step of the research, while the actual data analysis, while obviously important, plays a secondary role. However, a convincing design requires research questions to be broken down to manageable pieces. Thus, the big tradeoff in this perspective is between reliable inferences on very specific causal relationships on the one hand, and their broader context and complexity (and, possibly, theoretical relevance) on the other hand. The chapter first distinguishes between two general perspectives on causality, namely, one that puts the causes of effects in the foreground, and another that is more interested in the effects of causes. We will then introduce the potential outcomes framework before discussing ∗Chapter for Maggetti, Martino, Fabrizio Gilardi and Claudio M. Radaelli (2012), Research Design in the Social Sciences, SAGE Publications. †Associate Professor, Department of Political Science, University of Zurich, Switzerland. Email: gilardi@ipz.uzh.ch; URL: http://www.fabriziogilardi.org/.