Trygve Ottersen1, David B Evans2, Elias Mossialos3, John-Arne Røttingen4. 1. 1Department of International Public Health,Norwegian Institute of Public Health,Oslo,Norway. 2. 4Health Systems Research and Dynamic Modelling Group,Swiss Tropical and Public Health Institute,University of Basel,Basel,Switzerland. 3. 5Health Economics, Policy and Law,LSE Health and Social Care,London School of Economics and Political Science,London,UK. 4. 7Department of Health Management and Health Economics,University of Oslo,Oslo,Norway.