In the mid-1990s, a pair of Canadian researchers videotaping children on playgrounds made a simple observation that helped shift experts' views about bullying: When children bullied other children, they rarely did it alone. Research now suggests that bullies, their victims, bystanders, parents, teachers, and other adults in the building are all part of an ecology in schools that can either sustain or suppress bullying behaviors. And finding a solution to the problem requires a similarly broad, multilevel response, an interdisciplinary group of researchers argued earlier this year in a special issue of "Educational Researcher." Understanding the full measure of bullying is especially important now as districts, states, and federal education officials step up their efforts to combat the scourge in schools. Most recently, Massachusetts became the 42nd state to enact an anti-bullying law. However, finding a program that's been shown to work in every school context won't be easy. Studies of schoolwide anti-bullying programs in the United States have yielded only mixed success in reducing bullying behaviors. An article in the February issue of "Educational Researcher" reports that there is not a single, large-scale clinical trial of a schoolwide bullying-prevention program, a fact that highlights the need to conduct rigorous randomized trials in this area. It suggests that bullying will be reduced and/or stopped when prevention and intervention programs target the complexity of individual, peer, school, family, and community contexts in which bullying unfolds.