The main findings of this study are we did not observe a downward trend in both forms of bullying victimization, and more female students reported being bullied compared with male students, both traditionally and electronically. These findings echoed the previous findings[8, 9], and highlighted the gap between reality and the Healthy People 2020 goal on reducing bullying and identify female students as the priority group.
Olweus concluded that compared with traditional bullying, the prevalence of cyberbullying was actually quite low using the time series data from two large-scale studies in the U.S. and Norway[2]. The data from the U.S. sample (total n=447,000) showed that the average across time prevalences of being bullied verbally and electronically were 17.6% and 4.5%, and were 11.0% and 3.4% in Norwegian data (total n=45,000)[2]. However, according to YRBS data, there were 19.74% and 15.38% of high school students who were exposed to traditional bullying and cyberbullying during 2011-2017, indicating that in the past few years, cyberbullying is not a low frequent phenomenon[10], at least among U.S. adolescents.
In spite of increasing accessibility to smartphones and other Internet devices, Olweus found that there was no growth trend in the prevalence of being cyberbullied during 2006-2010, neither did the traditional bullying[2, 11]. For cyberbullying, the prevalence ranged from 15.4% to 18.4% in the U.S. and from 10.3% to 11.75 in Norway; for traditional bullying, the results were 15.4%-18.4% in the U.S. and 10.3%-11.7% in Norway[2]. We achieved a similar conclusion from YRBS data. Among U.S. high school students, the prevalences of being cyberbullied and traditionally bullied were both unchanged significantly from 2011 to 2017. Across the seven years，the prevalence ranged from 14.77% to 16.23% for cyberbullying and from 19.04% to 20.19% for traditional bullying.
Large studies indicate that there is a substantial overlap between cyberbullying and traditional bullying[12, 13], and the degree of overlap varies from over 90%[2] to 50%[14]. Olweus argued that cyberbullying created a few additional victims of bullying, given that the degree of overlap was up to 88% in the U.S. and 93% in Norway[2, 13]. However, YRBS data showed that the degree of overlap was only about 60%, and the overall prevalence of being cyberbullied only was 5.76% during 2011-2017, which meant that contrary to findings from Olweus, cyberbullying actually added a few new victims at least among U.S. adolescents.
Healthy People 2020 provides science-based national objectives for improving the health of Americans during 2011–2020. Healthy People 2020 objective IVP-35 is to reduce the prevalence of being bullied traditionally in the previous 12 months before the survey among U.S. high school students from 19.9% to 17.9%[5]. However, YRBS data showed that during 2011-2017, the prevalence of traditional victimization during the 12 months before the survey among students in grades 9 through 12 ranged from 21.99% to 19.04% and no linear decrease occurred, which suggested that more work is needed to address the issue of school bullying in the next few years. To achieve the Healthy People 2020 bullying goal[15], priority groups should be identified first. Consistent with the results from previous studies in U.S. high school students[6, 8, 16, 17], in our study, the self-reported prevalences of being cyberbullied and traditionally bullied among female students are both higher than male peers across the survey cycles, indicating that there are sex disparities in traditional and cyberbullying. The underlying cause for the unchanged trends for both female and male students may be that existing anti-bullying initiatives could reduce verbal and physical bullying effectively, but not relational bullying[9]. Relational bullying victimization ranked as the top bullying form among U.S. adolescents, and females were more likely to be involved in relational bullying according to Health Behavior in School-Aged Children study[18]. Societies should give high priority to interventions that focus on female students and relational bullying.
The findings in this study are subject to at least four limitations. First, YRBS data are self-reported, and the experience of being bullied traditionally or electronically may be affected by retrospective recall and social desirability biases[19]. Second, it should be noted that identical or similar measurement properties, including reference period, cutoff point, and context of bullying, must be used to compare the results from different studies. The recommended cutoff for the classification of being bullied is 2 or 3 times per month or more[13]. YRBS used at least once in the past 12 months for the criterion for classification, which led to higher prevalence estimates compared with Olweus’s studies. Third, we measured traditional and cyberbullying victimization by one single item respectively. The use of the single-item measure might possess non-optimal psychometric properties, however, the single-item measure can capture enough information when estimating and comparing the prevalence of bullying victimization[20]. Last, it was not possible to identify the reasons behind the non-declines in school bullying using YRBS data.