Why Causal Mechanisms and Process Tracing Should Alter Case Selection Guidance

Abstract

Advice on case selection in small- N research emphasizes controlling for confounding variables to facilitate inferential tests of a cross-case pattern. Yet many researchers embrace the “mechanismic worldview” and aim to construct explanations. Explanations differ from inferences because one explains an outcome at the individual case level. Hence, explanatory case studies are not simultaneously inferential tests, rendering prevailing case selection guidance ill fitting. This article provides an alternative outlook on case studies and case selection. It conceives of case studies as things that engage an analytical ideal type. Researchers can construct case-specific explanations by coupling the general claims of an ideal type with contextual analysis. In terms of case selection, if a case has contextual features that make it relatable to an ideal type, one can viably study that case in relation to the ideal type, regardless of the case’s other characteristics. This criterion diverges sharply from the conventional wisdom on case selection and can embolden unconventional comparisons.