Qualitative investigation of theoretical models: the value of process tracing

TLDR

Political scientists routinely use qualitative evidence to evaluate formal models, yet systematic guidance on this practice is lacking. This article seeks to fill that gap by offering three contributions, including new guidelines for process tracing in modeling. It shows that process tracing is as valuable as statistical testing for assessing models and provides tailored guidelines for its use. The study finds that formal models and qualitative evidence are frequently combined, and that process tracing is as important as statistical testing for empirical model assessment.

Abstract

Political scientists frequently use qualitative evidence to support or evaluate the empirical applicability of formal models. Despite this widespread practice, neither the qualitative methods literature nor research on empirically evaluating formal models systematically address the topic. This article makes three contributions to bridge this gap. First, it demonstrates that formal models and qualitative evidence are indeed frequently combined in current research. Second, it shows how process tracing can be as important a tool for empirically assessing models as statistical testing, because models and process tracing share a common focus on understanding causal mechanisms. Last, it provides new guidelines for using process tracing that focus on issues specific to the modeling enterprise, illustrated with examples from recent research.