This CDI Practice Paper by Melanie Punton and Katharina Welle explains the methodological and theoretical foundations of process tracing, and discusses its potential application in international development impact evaluations.
There is growing interest in exploring alternative, yet still robust, approaches to evaluating the impact of interventions. In international development, the rapid rise of experimental and quasi-experimental evaluation designs has its merits, but there are many instances where large sample sizes and the selection of control groups are not possible – or unsuitable. This is particularly so where the nature of the intervention and the context requires a small-n study, such as advocacy or research interventions that seek to influence policy through diffusion and networking. Process tracing offers much potential, as it is a qualitative method that uses probability tests to assess the strength of evidence for specified causal relationships, within a single-case design, and without a control group. While not extensively used in evaluation, it offers the potential to evaluate impact (including through ex-post designs) by establishing confidence in how and why an effect has occurred.
The focus of CDI’s work is on:
- Developing the potential of Process Tracing as an evaluation methodology
- Learning about how Process Tracing is applied, and its suitability in different contexts
- Sharing understanding about the strengths and limitations of Process Tracing