„The difference in the shares of low achievers in PISA between pupils from the bottom and top 25 % segment of the PISA index of socio-economic and cultural status (ESCS) is striking. As many as 33.8 % pupils from the bottom 25 % segment do not reach the basic level of competence in science, while only 7.6 % of those among the top 25 % on the ESCS index do not reach that level.“
EU-Kommission (Hrsg.), „Education and Training Monitor 2017“ (2017), S. 10