„According to the PISA 2018 survey, grouping students by ability into different classes is the predominant practice in Ireland and the United Kingdom, with more than 90 % of students attending schools where this is practiced. Besides Ireland and the United Kingdom, the majority of 15-year-old students are also in schools that group students by ability in different classes in the German and Flemish Communities of Belgium, Luxembourg, Malta, the Netherlands, Romania, Switzerland, Montenegro, North Macedonia and Turkey.“
EU-Kommission (Hrsg.), Equity in school education in Europe (2020), S. 137.