„It is suggested that socioeconomic indicators such as parents’ highest education level, parents’ highest occupation level, family income and size are important determinants of achievement. There is high probability of families with a high level of the SES (Anm.: SES = socioeconomic status) to offer their children a better quality of academic support availability. Parents’ highest education level and family income are suggested to be the long-term determinants of achievement and specifically the parental education level is the most important reason for the difference in student achievement. It is remarked that the increase in family income leads to school achievement at every level of education and generally the children of poor family have lower achievement.“
Univ.-Prof. Dr. Ekber Tomul u. a., The relative effect of student, family and school‑related factors on math achievement by location of the school (2021), S. 4.