This report evaluates scientific methods to study health inequalities with the aim of helping to narrow the health gap across Europe. Issues in the field of health inequalities are not new to policymakers and have, over the past four decades, been studied extensively by researchers from various disciplines. However, there is still substantial uncertainty about several important issues, such as the extent to which socioeconomic disadvantage causally affects health, and the effectiveness of interventions to reduce health inequalities. The report concludes that a range of new analytic methods are a “valuable addition to health inequalities researchers’ tool-box” and should be used as a complement to conventional research methods to resolve these issues and reduce the uncertainties. Examples of such new methods include “counterfactual” approaches to assess the causal effect of socio-economic conditions on health, and “natural experiments” to evaluate the effect of interventions on health inequalities.