Process tracing and congruence analysis to support theory-based impact evaluation

Abstract

Theory-based impact evaluations have been put forward increasingly as an alternative for counterfactual impact evaluations. However, this raises questions regarding the foundations of drawing causal inference on the basis of such approaches. Case study methods such as QCA (Quantitative Comparative Analysis), process tracing and congruence analysis are emerging as a way to match the methodological rigor of counterfactuals. While QCA relies on multiple cases, process tracing and congruence analysis are methods that claim to be able to draw causal inference within a single case. In this article, a completed theory-based impact evaluation of a European Social Fund intervention is used as a foundation to demonstrate and discuss the differences between process tracing and congruence analysis and their relative (dis)advantages.