On the Applicability of the Most Similar Systems Design and the Most Different Systems Design in Comparative Research

In comparative political research we distinguish between the ‘Most Similar Systems Design’ (MSSD) and the ‘Most Different Systems Design’ (MDSD). In the present work, I argue that the applicability of the two research strategies is determined by the features of the research task. Three essential distinctions are important when assessing the applicability of the MSSD and the MDSD: (1) whether or not variable interactions are studied at a systemic level or at a sub‐systemic level; (2) whether we use a deductive or inductive research strategy and (3) whether or not we operate with a constant or varying dependent variable. The article argues that the combination of these dimensions is essential for how the MSSD and the MDSD can and should be used in comparative research.