ABSTRACT
The general task of education to provide for national survival and development may be regarded as common to all nations. This never happens in isolation, and in today’s world of cross-national contacts and interdependence several common interests have arisen concerning the quality and quantity of the products of education systems. Among these are problems of yield and comparative quality of education system products, implications of student and workforce mobility across borders, accountability interests related to large-scale educational reforms and, in general, the need for valid and generalisable (i.e. genuinely scientific) information on education (Bloom 1969; Husén 1979; Purves 1987; OECD 1992; Tuijnman and Postlethwaite 1994).
