Dr. University Amsterdam, 1957. Dr. Netherlands School Economics, Rotterdam, 1966.
Staff, Centraal Planbureau, The Hague, Netherlands, 1955-1960. Research Association Econometrica, Netherlands School Economics, Rotterdam, Netherlands, 1960-1966. Acting Association Professor of Economics, University California Berkeley, 1962-1963.
Research Association, Social Systems Research Institute, Institution, University Wisconsin, Madison, 1963. Research Professor Economics and Social Sciences, Catholic University Louvain, Belgium, 1966-1971. Staff, Director, Centre for Operations Research and Econometrics, Belguim, Universities Louvain, Brussels, 1966-1969, 1971-1974.
Visiting Professor Econometrica, Graduate School Business, University Chicago, 1969-1970, University Pennsylvania, Philadelphia, Pennsylvania, 1984. Professor of Economics, Catholic University Louvain, Leuven, Belgium, 1971—. Association Editor, Econometrica, 1969-1972.
Editorial Board, European Economic Record since 1969.
One line of research consists in the development of the Hicks-Alien approach to consumer theory into the direction of a tool of empirical analysis. This has involved further elaboration of the theory (e.g. the Fundamental Matrix Equation of Demand Theory), collection of data (Netherlands 1921-1962), functional form specification (with H. Theil, the Rotterdam system) and statistical methodology of allocation systems (invariance for identity of residual class, negative definite matrix estimation). As a by-product, the way in which family composition may affect consumption patterns was elaborated.
Another line of research goes back to the beginning of my professional career as a member of the team for the construction of a macroeconometric model for The Netherlands to be used by the Central Planning Bureau.
Since the late 1960s, macroeconometric model construction has been undertaken for and under contract with the European Commission. This project consists of an interlinked set of identically specified national sub-models for European Economie Community member-countries. In the course of its existence, this COMET model has developed into a worldwide model with emphasis on the European Economie Community.