Paired comparison and theory development: Considerations for case selection

Despite the widespread use of paired comparisons, we lack clear guidance about how to use this research strategy in practice, particularly in case selection. The literature tends to assume that cases are systematically selected from a known population, a major assumption for many topics of interest to political scientists. This article speaks to this gap. It describes three distinct logics of paired comparison relevant to theory development, presents a simple way of considering and comparing them, and explores how this approach can inform more intentional research design, with particular attention to low information settings where substantial research is needed to ascertain the values of independent or dependent variables. The discussion underscores inter alia the need to be aware and explicit about the implications of case selection for the ability to test and build theory, and the need to reconsider the well-cited "rule" of not selecting on the dependent variable.