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Violence Research Centre


Dr Hannah Gaffney co-authored Effectiveness of schoolbased programs to reduce bullying perpetration and victimization: An updated systematic review and metaanalysis with her PhD supervisors Dr Maria Ttofi and Professor David Farrington.

Bullying emerged as an important research topic in the 1980s and is associated with many negatives outcomes for victims and perpetrators. The authors believe that “School bullying is an important target for effective intervention, and should be considered a matter of public health concern”.

The review aims to establish if school-based antibullying programmes are successful. An earlier review by Farrington and Ttofi (2009), found that intervention and prevention programmes succeeded in reducing bullying perpetration and victimisation, and the current report offers an update.

Studies included in the review evaluate intervention programmes that targeted bullying perpetration and/or victimisation outcomes in school‐aged children, between four and 18 years old. Cyberbullying is also considered, as previous research found an overlap between offline and online bullying.

Evaluations were conducted in different countries around the world, comprising Australia, Austria, Brazil, Canada, China, Cyprus, Czech Republic, Finland, Germany, Greece, Italy, Malaysia, the Netherlands, Norway, Romania, Spain, Sweden, Switzerland, South Africa, the UK, the USA and Zambia.

The authors conclude that school-based antibullying programmes are effective, however, big variations in the effects and reasons for these variations need further research. The review can be downloaded free of charge here



Gaffney, Hannah & Ttofi, Maria & Farrington, David. (2021). Effectiveness of school‐based programs to reduce bullying perpetration and victimization: An updated systematic review and meta‐analysis. Campbell Systematic Reviews, 17, 10.1002/cl2.1143



Hannah Gaffney is an affiliated member of the Violence Research Centre at the Institute of Criminology. She was awarded her PhD in Criminology in 2020 from the University of Cambridge. Hannah’s doctoral research concerned with ‘what works’ in school- and cyber-bullying intervention and prevention programs. Her work demonstrates that school programmes can be implemented to reduce bullying amongst youth, and that the effectiveness varies according to specific features of intervention programmes and evaluation methodologies.

Hannah was appointed as Betty Behren’s Research Fellow at Clare Hall College, Cambridge where her work will focus on examining ways in which violence (particularly sexual violence, intimate partner violence and hate-related violence) can be prevented using sexual and relationship education programmes in schools.


Selected publications

Gaffney, H., Ttofi, M. M., & Farrington, D. P. (2021). What works in anti-bullying programs? Analysis of effective intervention components. Journal of School Psychology, 85, 37- 56.

Gaffney, H., Farrington, D.P., & Ttofi, M.M. (2019). Examining the effectiveness of school-bullying intervention programs globally: A meta-analysis. International Journal of Bullying Prevention, 1, 14 -31.

Gaffney, H., Farrington, D.P., Espelage, D.L., & Ttofi, M.M. (2019). Are cyberbullying intervention and prevention programs effective? A systematic and meta-analytical review. Aggression and Violent Behavior, 45, 134 - 153.

Gaffney, H., Ttofi, M.M., & Farrington, D.P. (2018). Evaluating the effectiveness of school-bullying prevention programs: An updated meta-analysis. Aggression and Violent Behavior, 45, 111 - 133.