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Stephen S. Leff, PhD
Stephen S. Leff
Co-Director, Health and Behavior Research Affinity Group

Dr. Leff's background is in child clinical psychology, and he has broad training and expertise in intervention research, mixed methods, and in leading a range of federally funded research initiatives. His research goal is to use community-based participatory research (CBPR) to develop and validate school-based aggression and bullying intervention programs and assessment tools for urban minority youth.



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Stephen S. Leff, PhD, is the Co-Director of the Center for Violence Prevention at CHOP, a licensed Psychologist, and the William H. Bennett Professor of Psychology in Pediatrics at the Perelman School of Medicine at the University of Pennsylvania. His research focuses on aggression and bullying prevention programming, relational aggression which is the use of rumors and social exclusion to harm others, racial microaggressions, the community-based participatory research process which is working with community stakeholders to integrate their voices and perspectives into best practice empirically-supported programming, and Scientific Edutainment which integrates empirical science with the latest entertainment technology in order to make educational programming evidence-based, engaging and relevant to youth. Dr. Leff has been the recipient of six prior NIH grants, as well as a range of other federal, local, and foundation awards to support his intervention research. He is strongly committed to issues of diversity, equity, inclusion, and anti-racism.

His notable career accomplishments include:

  • PI on six prior National Institutes of Health (NIH) grants, including two school-based clinical trials
  • Developer of the first effective relational aggression intervention for minority youth in urban school settings (Friend to Friend)
  • Presentation on "The Need for Evidence-Based Bullying Prevention Programs" to the Congressional Anti-Bullying Caucus in 2014
  • Congressional briefing on bullying prevention in 2015
  • International Safety Media Award for Free2B Anti-Bullying Program, presented at the 12th World Conference in Injury Prevention and Safety Promotion in 2016
  • Feature on Good Morning America in 2017 for the Violence Prevention Initiative’s bullying prevention effort being recognized as a beneficial and impactful program serving the local community

Education and Training

BA, Duke University (Psychology and Religion), 1989

MA, University of North Carolina, Chapel Hill (Clinical Psychology), 1992

PhD, University of North Carolina, Chapel Hill (Clinical Psychology), 1996

Fellowship, Children's Hospital of Philadelphia (Clinical/Pediatric Psychology), 1998

Titles and Academic Titles

Co-Director, Center for Violence Prevention

Co-Director, Health and Behavior Research Affinity Group

Research Training Director, Leadership Education in Neurodevelopmental Disabilities (LEND)

Professor of Clinical Psychology in Pediatrics and Psychiatry

Professional Memberships

Bullying Research Network (BRNET), 2009-

Professional Awards

Community Service Award, Peace Islands Institute (for Violence Prevention Initiative), 2014

International Safety Media Award for Free2B Anti-Bullying Program, 2016

Jackson Healthcare Program of Excellence Award (in recognition of the Violence Prevention Initiative’s innovative approach to impacting lives in our community), 2017

Good Morning America recognized the Violence Prevention Initiative and its school-based bullying prevention programs as a beneficial and impactful program serving the local community, 2017

Publication Highlights

Links of Interest