In recent years, impact has become an important evaluation metric for creative practice researchers. It is no longer enough to claim that creative practice has intrinsic rewards, the assumption is that it will also affect change in some form or another. Yet, the means for evidencing impact are poorly understood, while the relatively short lifespan of a creative project can mean that there is often little opportunity to evaluate the long-term effect (or impact) of creative practice. To explore this gap, a case study of DeClick, a participatory arts project in the Netherlands, was employed. This study shows that by adopting a ‘theory of change’ approach, not only does it set out clear intentions for the project, but an analysis of underlying assumptions that link activities to impact leads to effective activity design and provides evidential methodology for evaluating project success. Subsequently, a mixed-methods approach is shown to evaluate impact in a way that values participation in creative practice as a meaningful experience. The approach explored through the case study acknowledges the challenges of evidencing long term impact. But also shows it is possible to evidence ‘pathways to impact’ using a social return on investment model for impact evaluation.