Published online by Cambridge University Press: 01 February 2019
This article reviews recent attempts to develop multi-method social scientific frameworks. The article starts by discussing the ontological and epistemological foundations underlying case studies and variance-based approaches, differentiating approaches into bottom-up, case-based and top-down, variance-based approaches. Case-based approaches aim to learn how a causal process works within a case, whereas variance-based approaches assess mean causal effects across a set of cases. However, because of the different fundamental assumptions, it is very difficult for in-depth studies of individual cases to communicate meaningfully with claims about mean causal effects across a large set of cases. The conclusions discuss the broader challenges this distinction has for the study of comparative politics more broadly.