„Having more books at home is conducive to consistently better performance on the PIRLS 2021 test, although this effect in not linear. The difference in performance between students who report having more than 200 books and those who report having between 101 and 200 books is considerably smaller than that between students who have between 101 and 200 books and those who have between 26 and 100 books. […] Students who had been engaged in various literacy-related games and activities before they went to school are also found to do better on the test than students who didn’t have that experience.“
Univ.-Prof. Dr. Zbigniew Karpiński, The experience of being bullied at school and its effect on reading proficiency in grade 4 (2023), S. 16.