Socioeconomic development has brought major improvements in global health. Advances in health care have played an important role. However, social determinants—social, economic, political, cultural, and environmental factors—heavily influence people’s demand for, access to, and use of health services. As a reflection of wider social inequalities, health systems tend to favour the better off, sustaining and sometimes amplifying health inequity (box 1).1

This is not inevitable. Healthcare systems and services can promote health equity if they are designed to maximise the “fit” between patients and providers.3 We use examples of health programmes taken from low, middle, and high income countries (Cambodia, Iran, Mexico, and the United States) to show how designing health services to take account of and work with wider socioeconomic determinants can improve health equity by enhancing service delivery and promoting uptake, particularly among the poor. Limited availability of data and limited attention to equity when evaluating health programmes make it difficult to reach definite conclusions, but in …