The Medical Research Councils’ framework is a framework for the development of effective, sustainable and scalable intervention design and evaluation for complex healthcare interventions. The framework has been criticized for not including theory-driven approaches to evaluation.

This article proposes a theory-driven approach to the design and evaluation of complex interventions by adapting and integrating Theory of Change into the MRC framework for complex interventions.

This approach was tested by using ToC within two randomized controlled trials and one non-randomized evaluation of complex interventions.

In conclusion, it was found that incorporating a ToC approach into the MRC framework holds promise for improving the design and evaluation of complex interventions, thereby increasing the likelihood that the intervention will be ultimately effective, sustainable and scalable.