The conditions in which we are born, grow, live, work and age are key drivers of health, wellbeing and inequalities in life chances. Preventing ill health related to these “social determinants of health” requires well-coordinated policies across many sectors, such as the economy, welfare, housing, education and employment. SIPHER will deliver novel evidence on the complex and interlinked consequences of policy decisions and associated costs and benefits. This will help our policy partner organisations - Sheffield City Council, Greater Manchester Combined Authority and the Scottish Government - to identify opportunities for the strategic alignment of policies across government sectors and give decision makers the confidence to change the way major investment decisions are made.