An ongoing challenge in evaluation is the need to make credible causal claims linking observed results to the actions of interventions. This ILAC Brief argues the need for a different perspective on causality, where interventions are seen as contributory causes to certain results.

The Brief further argues that theories of change are models showing how an intervention operates as a contributory cause. Using theories of change, approaches such as contribution analysis can be used to demonstrate that the intervention made a difference and to explain how and why.