The Realist Approach to Social Policies (RASP) study: A study protocol for mixed-methods realist research combined with institutional action research, to reduce socioeconomic health inequalities through systems change

Introduction Health inequalities are rooted in inequality in vital resources for health, including financial resources, a supportive informal network, a stable living situation, work or daytime activities, or education and literacy. About 25% of Dutch citizens experience deprivation in such resources. Social policy consists of crucial instruments for improving resources in those groups, but can also have adverse effects and lead to additional burden. This project aims to contribute to the reduction of health inequalities through 1) better understanding how social policy interventions can contribute to reducing health inequality through the redistribution of burdens and resources, and 2) developing anticipatory governance strategies to implement those insights, contributing to a change in social policy systems. Methods Two systems approaches are combined for establishing a systems change. Firstly, a realist approach enables insights into what in social policy interventions may impact health outcomes, for whom, and under what circumstances. Secondly, an institutional approach enables scaling up these insights, by acknowledging the crucial role of institutional actors for accomplishing a systems change. Together with stakeholders, we perform a realist review of the literature and identify existing promising social policy interventions. Next, we execute a realist evaluation of selected social policy interventions in seven municipalities, ranging from small, mid-size to large, and in both urban and rural settings. Simultaneously, through action research with (national) institutional actors, we facilitate development of anticipatory governance strategies. Discussion By combining a realist approach and an institutional approach, this study protocol not only sheds light on cross-domain impacts on health through realist review and evaluations, it also provides insight into how systems can be changed to benefit he