„The importance of out-of-school factors, including students‘ socio-economic background and the educational level of parents or the language spoken at home cannot be overstated. Significantly reducing the proportion of low achievers, therefore, would require a combined approach that simultaneously targets a range of factors both in and out of school.“
EU-Kommission (Hrs.), „Structural Indicators for Monitoring Education and Training Systems in Europe 2015“ (2015), S. 23