The classic image of school bullying--a big kid picking on a little kid on the playground--is an oversimplification of a range of cruel behaviors affecting nearly a third of America's school children.
What was once dismissed as an unpleasant but unimportant aspect of growing up is now understood to be a major predictor of long-term problems for both bully and victim, a contributor to the widely held misperception among students that their schools are among the more dangerous places in their environments, and a common thread in the rash of school shootings over the past decade.
Bullying involves three conditions:
• Negative or malicious behavior
• Behavior repeated over time
• An imbalance of strength between the involved parties 
While this clearly fits the conventional perception of direct, physical bullying associated with boys, it also encompasses the indirect forms of aggression--gossiping, slander and exclusion more commonly attributed to girls.
 Bullying is Not a Fact of Life, p. 4; National Mental Health Information Center, Substance Abuse and Mental Health Services Administration, 2003, available at http://www.mentalhealth.samhsa.gov/publications/allpubs/SVP-0052/; accessed 11 August 2004