- Classroom intellectual composition positively affects the student’s academic achievement, and compositional quality and personal ability interact.
- The low-resource students’ loss is greater than the high-resource students’ profit, and in mixing, the high-resource students’ loss is smaller than the low-resource students’ gains.
- The richer the composition, the better the student’s chances for higher scholastic achievement.
- The effect of classroom composition increased as the level of previous achievement decreased. The poorer the student’s personal resources, the more sensitive he or she was to the quality of the educational environment.
- Homogenous classes did not provide any advantage in academic achievement; on the contrary, advantage was held by heterogeneity.
- Low-resource students transferred from a low homogenous class to a heterogeneous class will profit more than high-resource students will lose when transferred from a high homogeneous class to a heterogeneous one.
- Ethnic origin per se, compared to personal ability and, to a lesser degree, to socioeconomic background, is a weak, if not insignificant, factor in explaining academic achievement as measured by objective tests.
- As a proxy for the intellectual dimension, socioeconomic composition is preferable to ethnic composition, at least when the principal aim of integration is educational advancement of low-resource students.
- Classroom intellectual composition positively affects the student’s objective academic achievement, beyond the potent effect of his or her personal intellectual resources, here tightly controlled. Implicitly it means that the classroom intellectual composition conditions, to some extent, the quality of the student’s socio-learning environment.
- There is an interaction between personal and compositional resources, and that the compositional effect is stronger among low-resource students.
- The heterogeneous class is more advantageous for low-resource students than the low homogenous one, and there is no real disadvantage for high-resource students in the heterogeneous class versus the high homogenous one.