This framework provides the basis of the synthesis phase of the plan for the analysis of the data, that reflects the systemic context from which the measures are taken. The context and drivers for the approaches taken to the evaluation design are outlined. How the challenges posed by attempting to collectively evaluate multi-site, multi-component and multi-level interventions implemented in real-world complex community systems to create the conditions for measurable and detectable population-level impact are discussed. Applying complexity theory to inform evaluation design of interventions implemented into real-world community systems to inform policy impact is currently a major area of inquiry and development in the field of evaluation. This is an applied example about how this has been approached in a multi-site community systems-based approach to tackle obesity.