Process Tracing and Historical Explanation

This article offers a state of the art of methodological writings on process tracing. Its goal is to encourage the more self-conscious and transparent use of this method in security studies. The article considers process tracing for both theory testing and theory development. First, with theory testing, the article discusses the logic of historical explanation and the use of sequential analysis. It then focuses attention on two kinds of process-tracing tests: hoop tests and smoking gun tests. The article explores the mechanics through which these tests allow investigators to pass judgment on hypotheses. Second, with theory development, the article examines the use of counterfactual analysis and inductive discovery in the process of novel hypothesis formulation. The article shows how process-tracing researchers use event analysis to formulate original explanations of specific outcomes in particular cases.