William is a social epidemiologist in the Department for Social Policy and Intervention at the University of Oxford. His research focuses on identifying cost-effective combinations of interventions to promote adolescent health and education across Africa. His methodological interests include causal inference and the use of multilevel (random effect) models to account for the interconnected and hierarchical nature of social vulnerabilities. He is an honorary research affiliate in the Centre for Social Science Research at the University of Cape Town, and he completed his PhD at the London School of Hygiene & Tropical Medicine. He has research and health policy experience with the World Health Organisation, World Food Programme, UNICEF, and Government Ministries in Brazil, Ethiopia, Kenya, and South Africa.