Process Tracing Methods and International Studies

Process tracing (PT) is a case study method that enables scholars to study how causal processes (also known as causal mechanisms) play out in real-world cases. Despite the increasing popularity of the method in international studies, there is still considerable disagreement among scholars about how to understand the process actually being traced and how these processes can be studied empirically. This article tries to bring clarity to these disagreements by arguing that there is not one correct variant of PT, but instead several distinct variants of PT methods that differ based on the positions scholars take on what is being traced and how it can be traced. First, some scholars work with simple, abstract (minimalist) process theories, whereas others disaggregate process theories into parts composed of actors engaging in activities. Second, some scholars contend that inferences that assess the difference that a process makes for outcomes can only be made through controlled comparisons of cases. Others posit that we should study processes through the empirical traces left by their operation within cases. Finally, there are scholars who contend that causal processes in international studies involve social actors, meaning that more interpretive methods should be combined with more traditional PT. The article illustrates how different variants of PT have been used in published work within international studies, followed by a discussion of key challenges with using PT methods.