Wrote his thesis “Studies in Health Insurance and Econometrics” at Leiden University.
Since 1986 he is professor of Health Insurance at the Erasmus University Rotterdam.
His teaching and research focus on managed competition in health care, competitive health insurance market, risk selection, moral hazard, risk equalisation, managed care and priority choices in health care.
He has experience as a governor and adviser of insurance companies, political parties, government, research institute, hospitals and other health care organizations.
He serves (served) as member of many advisory committees and the editorial Board of scientific journals.
As a consultant, e.g. for the World Bank and the World Health Organization, he has studied the health care systems in Chile, Ireland, Israel, New Zealand, Poland, Russia, South Africa and Sweden.
He is one of the founding fathers of the European Risk Adjustment Network.
Previous positions are Programme Director of the Master Health Economics, Policy and Law at Erasmus University and Chair of the iHEA Jury-Committee for the annual Arrow Award for best paper in health economics.
1986 – Present:  Professor of Health Insurance, Erasmus University Rotterdam
1983 – 1986:   Associate professor, Erasmus University Rotterdam
1981: Visiting research associate, RAND Corporation, Santa Monica, U.S.
1976 – 1982:   Assistant professor, University of Leiden
1973 – 1976:   Research-assistent, University of Leiden