His research focuses on the methodology of welfare economic evaluations in health care. His work has covered topics like optimal decision rules, normative foundations of economic evaluations in health, measurement and valuation of informal care and productivity costs, incorporating equity considerations in economic evaluations as well as the monetary value of health gains. In addition, he has performed work on the link between economic evaluation and health policy, behavioral economics and public health economics. He published extensively on these topics including in journals like Health Economics, Journal of Health Economics, Medical Decision Making, Social Science & Medicine and British Medical Journal. Werner has been involved in several courses taught in the bachelor phase as well as in the international Master of Health Economics, Policy and Law (HEPL) of the Erasmus School of Health Policy & Management. So far, he has supervised 12 completed PhD theses. From 2012-2018 he was Dean of ESHPM. Werner is an Associate Editor of Health Economics and a member of the Editorial Boards of the European Journal of Health Economics, PharmacoEconomics and Cost-Effectiveness and Resource Allocation. He is a member of the European Commission Expert Panel on Effective Ways of Investing in Health and the independent chairman of the Foundation for Top Clinical Mental Health Care (TOPGGz) and chairs the Erasmus Initiative Smarter Choices for Better Health of the Erasmus University Rotterdam.