„In primary education, the data are extremely worrying. According to the International Association for the Evaluation of Educational Achievement (IEA) assessment, 29 % of 4th grade students reported that they suffered bullying each month and 14 % reported being bullied on a weekly basis.“
Elena Govorova u. a., Predicting Student Well-Being: Network Analysis Based on PISA 2018 (2020), S. 1.