ABSTRACT
During the 1960s and 1970s, a universal trend towards greater heterogeneity and integration in education reflecting fundamental changes in the notions of civic, social, and educational equality, developed. This universal trend notwithstanding, a public and educational controversy continues to revolve around the homogeneity-heterogeneity issue. Teachers, well aware of the difficulties in handling heterogeneous classes, raise first of all the argument of "didactic fit", whereby adaptation of content, level and pace of learning to differential ability is beneficial for all students, strong and weak. The claim to integrate students of different ability, social class and ethnic background is raised because segregation forms and perpetuates poor socio-learning environments and is thus conceived as impairing equality of educational opportunity for weak students who are usually members of weaker social groups. The independent variable is thus seen as the quality of the socio-learning environment as determined by the aggregate level of student learning-relevant resources.
