Stop Bullying: What's bullying, when is it most common?

Is a one-time squabble between friends or siblings bullying? Probably not, says Nancy Mullin, who has spent the last two decades researching and working on bullying prevention.

"Bullying generally happens more than once," she said. "It invariably involves some sort of power imbalance - size, age, popularity. There is always some power differential." 

"It’s not bullying if two kids get into a fight or two kids who are friends call each other names," she said. "It could be bullying if you have an older sibling who is just always doing something to bully a younger sibling. Or if you have a popular kid in school who is chronically using put downs against younger kids or less popular kids."

Bullying actually is most common in fourth to seventh grade, Mullin said.

By high school, there's an increase in adolescent sexual harassment, she said. Boys, for instance, are making comments about girls' bodies and their sexual proclivity. Kids are snapping bras or jock straps. They are spreading rumors about sexually transmitted diseases and targeting gay and transgender kids. 

"The labels are different, in part, because we should be doing something very different," Mullin said. "If something is sexual harassment, there are very strict policies in schools that need to be followed and it may even need to include calling the police. If you have two third graders get into a fight, you probably can stop it before anything bad happens. But if that happened in high school, you would be calling it assault as we expect high school age kids to behave in different ways."

According to StopBullying.gov, a federal website, one large study found that about 49 percent of kids in fourth to twelfth grade have reported being bullied by other students at school at least once in the past month. And most of that happened at school, on school grounds or on the school bus.

A study of middle school students found that about 30 percent of bullying happened in the classroom, 30 percent in the hallway or lockers; 23 percent in the cafeteria; 20 percent in gym or physical education class; 12 percent in the bathroom; and 6 percent on the playground or recess, according to StopBullying.gov.

"It peaks in those middle years and tapers off, but it never disappears," she said. "We all know of adult bullies."