Bullying includes hitting and teasing, as well as more passive forms such as exclusion from conversations and play. Bullying does not include fighting between equally strong children. The broad definition of bullying does not show which forms are most prevalent in which country, or the duration and intensity of bullying.

Data are drawn from school-based samples from the Health Behaviour in School-aged Children Survey. Bullying estimates are calculated using reported rates of bullying and being bullied weighted by sample numbers for 11-, 13- and 15-year-old boys and girls.