Fons J. R. van de Vijver is Professor of Cross-Cultural Psychology in the Department of Psychology at Tilburg University.
Ype Poortinga is Emeritus professor of cross-cultural psychology at Tilburg University in The Netherlands, and at the Catholic University ofLeuven in Belgium. He has been president of the International Test Commission, the International Association for Cross-Cultural Psychology(IACCP), the Dutch Psychological Association (NIP), and the European Federation of Professional Psychologists Associations (EFPA). Hismost consistent research interest has been in the conditions under which psychological data obtained in different cultural populationscan be meaningfully compared.