A review of programs designed to prevent bullying has found that they led to decreases in victimization ranging from 17 to 23 percent. More intensive and long-lasting programs were most effective. Successful elements included parent meetings, improved playground supervision, and firm disciplinary methods, such as serious talks with bullies, sending them to the principal, and depriving them of privileges. Work with peers, including peer mediation or mentoring, was associated with an increase in victimization. The review was done for the Campbell Collaboration, which analyzes research findings in criminology.
Anti-bullying programs have a greater impact on children 11 or older. This may be because older children have superior cognitive ability, are less impulsive and more likely to make rational decisions. Study authors David Farrington and Maria Ttofi of Cambridge University recommend development of an international a system of accreditation for anti-bullying programs. They suggest cost-benefit analyses of anti-bullying programs, because saving money is a powerful argument to convince policy-makers and practitioners to implement intervention programs.