Research into the prevalence of bullying is important to enable the correct allocation of resources to prevent and end bullying. One problem when gathering knowledge in how prevalent bullying is, is the considerable variation in percentage points in research studies. The aim of this study was to analyze how the estimated prevalence in Swedish national population-based studies of peer bullying victimization is related to how it is defined and measured.

The analysis focused on national population-based studies in Sweden, in order to ensure that the sampling and cultural aspects of data collection were similar throughout the period. Data came from three sources: 1) a scoping review of peer bullying victimization in Sweden, 2) reports from Swedish government agencies and non-government organizations that were not included in the scoping review, and 3) data from the Health Behaviour in School-aged Children (HBSC) Sweden 1993–2017 study.

The results showed that although the estimated levels of bullying victimization depend on the measurement method, they all followed a similar pattern over time with a higher prevalence of bullying in recent years. The study raised conceptual inconsistencies between bullying, peer aggression, and peer victimization, which are further discussed in relation to prevalence and measurement.