Bullying is defined as unwanted, aggressive behavior that may be repeated and involves a real or perceived imbalance of power. Making threats, spreading rumors, attacking someone physically or verbally, and excluding someone from a group on purpose are all examples of bullying. Cyberbullying, or bullying that uses electronic technology, is different from other types of bullying in that it can happen at any time, messages and images can be posted anonymously and distributed quickly via the Internet, and they can be very difficult to delete after posting.1

There is no specific factor that puts children at risk of being bullied or bullying others, although some groups, such as lesbian, gay, bisexual, or transgendered youth; youth with disabilities; and socially isolated youth may be at higher risk.2 Being bullied has been associated with a wide range of short- and long-term emotional, physical, and developmental consequences, including depression, anxiety, headaches, sleeping problems, stomach ailments, and decreased academic achievement. Children who bully are also more likely to engage in violent and risky behaviors, such as drug and alcohol use and early sexual activity. Even children who witness bullying can be negatively affected.3

In 2013, 19.6 percent of high school students reported that they had been bullied on school property in the past year and approximately one in six high school students (14.8 percent) reported having been electronically bullied through e-mail, chat rooms, instant messaging, Web sites, or texting (Figure 1). The likelihood of being bullied varied by a number of factors, including sex, grade level, and race and ethnicity. Females were more likely than males to have been bullied on school property (23.7 versus 15.6 percent, respectively) and more than twice as likely as males to have been electronically bullied (21.0 versus 8.5 percent, respectively).

Younger high school students were also more likely to report being bullied than older students: 25.0 percent of 9th-graders reported being bullied at school compared to 13.3 percent of 12th-graders (figure 1). Similarly, 9th-graders were slightly more likely than 12th-graders to report being bullied electronically (16.1 versus 13.5 percent, respectively).

bullied students by grade and location

Figure 1 Source

Non-Hispanic Black students were less likely to report being bullied on school property or bullied electronically (12.7 and 8.7 percent, respectively) than all other racial and ethnic groups (Figure 2). In comparison, non-Hispanic White students were significantly more likely to report electronic bullying (16.9 percent) than non-Hispanic Asian, Hispanic, and non-Hispanic Black high school students (12.9, 12.8, and 8.7 percent, respectively). Evidence-based recommendations to reduce bullying and its associated risks include both school-based programs that teach students about violence prevention and individual and group cognitive-behavioral therapy interventions for students exposed to violence.4, 5

bullied students by race and location

Figure 2 Source

Data Sources

Figure 1. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. High School Youth Risk Behavior Survey. Accessed September 20, 2014.

Figure 2. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. High School Youth Risk Behavior Survey. Accessed September 20, 2014.


1 Gladden R. M., Vivolo-Kantor, A.M., Hamburger, M., & Lumpkin, C. (2014). Bullying surveillance: Uniform definitions and recommended data elements (PDF). Version 1.0. Atlanta (GA): Centers for Disease Control and Prevention, National Center for Injury Prevention and Control.

2 U.S. Department of Health and Human Services. Stop Bullying: Risk Factors. Accessed September 20, 2014.

3 U.S. Department of Health and Human Services. Stop Bullying: Effects of Bullying. Accessed February 16, 2015.

4 The Community Guide. Violence Prevention: School-Based Programs. Accessed March 2, 2015.

5 The Community Guide. Violence Prevention: Reducing Psychological Harm From Traumatic Events Among Children and Adolescents. Accessed March 2, 2015.


Statistical Significance Test

Calculate the difference between two estimates:

Calculated Z-Test Result 0.9567433 Not statistically significant

We follow statistical conventions in defining a significant difference by a p-value less than 0.05 where there is a less than 5% probability of observing a difference of that magnitude or greater by chance alone if there were really no difference between estimates. The 95% confidence interval includes a plausible range of values for the observed difference; 95% of random samples would include the true difference with fewer than 5% of random samples failing to capture the true difference.

This website allows comparisons between two estimates using the independent z-test for differences in rates or proportions. This test is appropriate for comparing independent populations across years (e.g., 2011 versus 2012) or subgroups (e.g., Male versus Female) on corresponding measures. To the extent possible, the functionality of this application has limited estimate comparisons based on appropriate use of the independent z-test. However, some tables present subgroup categories within broader categories that will allow comparisons between non-independent populations (e.g., low birth weight and very low birth weight). Users should exercise caution when interpreting these test results, which will frequently overstate statistical significance.

For some tables, the website does not allow for comparisons between two estimates, even though the data represent independent populations. Generally, this is because the standard errors were not publicly available at the time this website was created.