RationaleSocial inequalities in health are a major challenge to public health in Europe and hence a priority topic for the EU. While the average level of health in EU countries has continued to improve over the last decades, differences in health between advantaged and disadvantaged sections of the population within each country remain substantial. A broad spectrum of policies influences the determinants of health inequalities. Such interventions are seldom evaluated for their impact on population health in general and even more rarely for their differential impact on different socioeconomic groups. There is an urgent need to extend and strengthen the evidence base on differential policy impact, to help identify the most effective ways to reduce health inequalities in different EU countries. Methodologically, this is a highly challenging task for which traditional experimental evaluation designs are neither adequate nor feasible.Objectives1 Develop, evaluate and refine methodologies for assessing the effects of social, economic and health policies on the pattern and magnitude of health inequalities among socioeconomic groups.2 Assess the differential health effects by socioeconomic group of ‘natural policy experiments’ in the fields of unemployment and poverty reduction; tobacco and alcohol control; and access to education and preventive health care.3 Synthesise the evidence from the findings of objectives 1-2, and actively engage users in the research in order to promote transfer of knowledge for policy and practice with maximum effectiveness.ApproachNew methods of policy analysis and evaluation of natural experiments will be combined with a unique longitudinal dataset of health determinants and health outcomes by socioeconomic group in more than 20 European countries covering several decades, in order to generate new knowledge on differential effects of policies targeting the strategic drivers of health inequalities.