„Unlike most elementary school systems, secondary schooling is generally characterized by the grouping of learners in one way or another, based on the rationale that teaching is easier and more effective in groups of students with more homogeneous abilities and interests.“
Dr. Michael Becker u. a., „The Differential Effects of School Tracking on Psychometric Intelligence“ in „Journal of Educational Psychology“, 2012, Vol. 104, No. 3, S. 684