Introduction

The primary purpose of pathway analysis is to build knowledge about the causal mechanisms that link X1 to Y across settings. This implies the need to perform comparative analyses that can generate knowledge and/or hypotheses about the broader population of cases that feature the X1/Y relationship. Before delving into the details of case selection, it is important to consider how researchers should prepare for pathway analysis. As an initial matter, researchers must clarify their specific goals. Once oriented to the basic task, they should: (1) determine whether the basic analytic requisites of pathway analysis are met; (2) identify what is already known about the X1/Y relationship; and (3) take stock of relevant measures.

The threshold task: clarifying the goals of pathway analysis

The purpose of using pathway analysis differs from other, more familiar types of research, which is why it is important for researchers to clarify these goals from the start. On this score, James Mahoney and Gary Goertz (2006) usefully distinguish between two ideal types of research in the social sciences: causes of effects and effects of causes. Causes-of-effects research seeks to provide “thick description” of the emergence of singular events or outcomes in particular settings (Mahoney and Goertz 2006; see Brady and Collier 2004; Geertz 1973). For US politics or history research, for example, possible questions might include: Why World War II? Why did the New Deal coalition collapse? What factors caused the most recent financial crisis? Why did the US Supreme Court decide Bush v. Gore as it did? For these types of questions, case selection is driven mostly by the substantive importance of the outcome to be explained, and the research primarily emphasizes case-specific internal validity (“Did the research get the story right?”), and not external validity (“Do the story's lessons apply in other contexts?”), although scholars often try to draw some broader lessons from their detailed descriptions.