What is Process Tracing Actually Tracing? The Three Variants of Process Tracing Methods and their Uses and Limitations.

The paper is structured into three parts. First we briefly introduce the existing orthodoxy regarding how PT methods are defined. This is followed by a presentation of the three variants of PT, focusing on their differing analytical purposes, what each variant is tracing in practice, and the degree to which the variants can be nested in mixed-method designs. Exemplary studies of each variant are used to illustrate the key differences across the variants. The paper concludes by summarizes the commonalities and differences across the three variants of PT.