„Many education systems have created homogeneous populations (based on ability) through stratification, tracking policies and ability grouping, and established well-defined and inflexible education pathways from compulsory schooling into further education and training to ensure that instruction is tailored to the specific needs of relatively homogeneous groups (defined by ability, interests and/or preferences).“
OECD (Hrsg.), „The Resilience of Students with an Immigrant Background“ (2018), S. 227