Surveys completed by middle school and high school students between 1998 and 2010 suggest that instances of both verbal and physical bullying dropped by roughly half, with much of the decline seen specifically among boys.
Study author Jessamyn Perlus, a fellow in the division of intramural population health research with the Eunice Kennedy Shriver National Institute of Child Health and Human Development, described her team's findings as "encouraging."
"In recent years, there has been more attention to anti-bullying efforts, such as prevention programs, and responses to bullying have been incorporated into school policies," Perlus noted. "We hope that these prevention efforts, and the additional attention and awareness of the problem of bullying, may be the reason for the decline."
Perlus and her colleagues reported their results in the April 17 online edition of the American Journal of Public Health.
During the study period, four surveys were conducted among a nationally representative sample of students attending grades 6 through 10. Each survey included roughly 9,000 to 16,000 teens.
Those polled were asked to indicate how much they had engaged in bullying in school during the prior two months. Bullying was defined as involving two or more people of unequal strength or power, and included verbal teasing and insulting; excluding or ignoring peers; physical abuse; the spreading of false and negative rumors; and/or making sexual jokes.
Off-campus bullying -- including cyber-bullying -- was not covered by the survey. In addition, students were asked to indicate the frequency with which they carried a weapon, such as a gun or knife.
The researchers found that weapon-carrying did not fall off during the study period, and white students were actually slightly more likely to pack a weapon in 2010 than they had been in 1998.
However, fewer students said that they had been a victim of bullying in the same timeframe, with rates dropping from nearly 14 percent to just over 10 percent. That decrease was seen primarily among boys.
An even more dramatic drop was seen among those students who said they had instigated an act of bullying. That figure fell from nearly 17 percent in 1998 to below 8 percent by 2010.
Bullying rates varied, however, when broken down by different groups. For example, while bullying among white students fell by 64 percent in the study timeframe, it dropped only 30 percent among black students.
Younger students (in grades 6 through 8) also saw bigger declines than older students (in grades 9 and 10), the findings showed.
When looked at by gender, bullying remained more common among boys than girls, with one exception: In the 2010 poll, girls were found to engage in more social ostracizing than boys.
Name-calling and social ostracizing were found to be the most common types of bullying in general, and these also saw the sharpest decline over the years, according to the report.
"However, we suspect these bullying behaviors are different in an out-of-school context," noted Perlus. "Particularly with technology that lends itself to cyber-bullying."
Stephen Russell, director of the Frances McClelland Institute for Children, Youth, & Families at the University of Arizona in Tucson, agreed with Perlus that the findings were good news.
"It is encouraging to see that the public education policy attention to bullying may be slowly paying off," he said.
Russell cautioned, however, that the study didn't touch specifically on instances of bullying that are rooted in discrimination, a tricky aspect of social ostracizing that he said students are prone to justify as "just normal."
"I've been advocating for inclusion of discrimination experiences [and] discriminatory bullying in large-scale surveys for a while now," he said. "And that, along with inclusion of cyber-bullying, will be important to understand over time."
Visit the U.S. Department of Health and Human Services for more on bullying.