1. Centre for International Health, University of Bergen, Bergen, Norway
2. Department of Health System, Impact Evaluation, and Policy, Ifakara Health Institute, Dar es Salaam, Tanzania
3. Department of Global Health and Development, Chr. Michelsen Institute, Bergen, Norway
4. Department of Economics, University of Oslo, Oslo, Norway
5. Department of Global Health and Development, London School of Hygiene & Tropical Medicine, 15-17 Tavistock Place, London, UK