„On average, individuals with high educated parents have better PIAAC scores than those whose parents had low educational achievement. While 25 % of individuals whose parents had below upper secondary are at the bottom in terms of literacy scores, this represents only 5 % of those whose parents had achieved tertiary education, while the reverse is found for the highest test scores. The impact of parental education on test scores is more marked for numeracy: 30 % of those at the bottom numeracy scores have a parent with low education.“
OECD (Hrsg.), A Broken Social Elevator? How to Promote Social Mobility (2018), S. 253.