Evaluating how interventions contribute to change is especially challenging in complex settings. Results often emerge over time, involve multiple actors, and are shaped by factors beyond the control of a single intervention. This makes it difficult to explain what difference an intervention actually made.
Contribution analysis (CA) offers a way to address these challenges. It helps build credible explanations of how and why an intervention contributed to observed changes, alongside other influences.
As CA has been applied in new contexts, its practice has also become more varied. This has led to uncertainties about what CA involves, the types of contribution claims it supports, and how quality should be assessed.
This guidance note serves as a shared reference for the high-quality application of CA. Aimed at experienced evaluators and evaluation commissioners, it sets out six core steps spanning theory building and theory testing (figure 1).
Figure 1. Steps of Contribution Analysis
Figure 1. Steps of Contribution Analysis
Stay tuned for a companion textbook on contribution analysis, currently in development.