Development and evaluation of system dynamics methods to engage with policy makers on the prevention and control of diabetes in a middle income region Diabetes is a serious and growing problem globally. Evidence suggests diabetes disproportionately affects people in low- and middle-income countries, where 80% of people with diabetes live, both in terms of numbers of people affected as well as outcomes and deaths. Diabetes affects between 10 and 20% of the adult population in the Caribbean region with deaths due to diabetes estimated to be 35% higher than in the neighbouring United States. Not only are prevalence and mortality a large burden but also rates of complications such as lower-limb amputation are also high. Much of the high burden of diabetes can be attributed to major risk factors such as physical inactivity and obesity.  Health systems with limited resources in these developing countries are struggling to meet the growing epidemic. There is a strong political will in the region to tackle diabetes and other non-communicable diseases (NCDs). In 2007, the Heads of Government of the Caribbean Community put forth the Port of Spain Declaration (POSD) on NCDs, definitively challenging the high burden of these diseases in the region and pledging action through policies to strengthen prevention and treatment.  This laid the groundwork for a global political movement to recognise NCDs on the public health agenda culminating in the United Nations High Level (UNHLM) meeting on NCDs in September 2011.  Both the POSD and UNHLM strongly emphasise the importance of policy measures for reducing NCD risk factors and put forth policies and targets.  However, evidence on how to achieve a reduction in overweight/obesity and physical inactivity and subsequently reducing NCDs at the population level is scarce, particularly in developing countries. While the risk factors and determinants of NCDs like diabetes are well studied and established, research has not been able to conclusively demonstrate real-world interventions that can reduce their popburden or change the course of the epidemic.   Systems science, which combines multiple factors and complex interrelationships, may offer a solution to evaluating and testing policies for diabetes reduction. It does this by explicitly taking into account system behaviour that is non-linear and complex, with feedback loops and time delays. Within systems science, system dynamics modelling is a methodology incorporating input from experts and stakeholders and combining that with quantitative research evidence to produce a map of a system with the ability to simulate outcomes by changing parameters. The approach has been used effectively in a wide variety of fields including engineering, agriculture, energy planning, business dynamics, and health including diabetes. However, few models have been developed for use in middle-income countries.  This study will be the first to explicitly develop a model for diabetes in developing countries, drawing from work successfully conducted by the Centers for Disease Control in the United States and their model for diabetes. The study will apply the rigorous qualitative methods required by interviewing stakeholders, experts and policy makers in the region as well as gathering evidence from research published on risk factors, outcomes, and health system performance for diabetes in the Caribbean. The study will use the developed model to engage stakeholders and policy makers in time for the on going evaluation of the POSD as a tool for effective policy planning. It will also evaluate the utility of this method in the region in engaging policy makers to think in terms of systems and with long time horizons. The results of this development study will be used to build a larger model incorporating economics and costs, which can then be adapted and used in other low- and middle-income countries. The Global Challenges Research Fund (GCRF) supports cutting-edge research to address challenges faced by developing countries. The fund addresses the UN sustainable development goals. It aims to maximise the impact of research and innovation to improve lives and opportunity in the developing world.