Anti-bullying intervention effects are weak, and RCT designs show even smaller effects than earlier meta-analyses suggested¶

Claim · All claims
Evidence · 1 study (2 entries) · associational r2 · q2 · i1 small
Currency · newest study 2023 · not yet checked against its sources · not reviewed by a person

Subclaims¶

q2 i1 An updated meta-analysis found weak intervention effects (mean odds ratio = 1.22, CI = 1.09–1.38), marginally worse than in 2009. → Herbert W. Marsh 2023 q2 i? A 2022 meta-analysis concluded intervention effects were very small to small and marginally effective. → Herbert W. Marsh 2023 (2)

Evidence¶

Herbert W. Marsh 2023¶

Herbert W. Marsh, Jiesi Guo, Philip D. Parker, Reinhard Pekrun, Geetanjali Basarkod, Theresa Dicke, et al. (2023). Peer Victimization: an Integrative Review and Cross-National Test of a Tripartite Model. Educational Psychology Review. https://doi.org/10.1007/s10648-023-09765-x

q2 · i1 · associational · r2

The review reports that the updated Farrington meta-analysis "found weak effects (mean odds ratio = 1.22, CI = 1.09–1.38) marginally worse in 2019 than in 2009", indicating post-2009 studies were not stronger than earlier ones.

"However, in updating their classic meta-analysis, Farrington and colleagues (Gaffney, Ttofi, & Farrington, 2019) found weak effects (mean odds ratio = 1.22, CI = 1.09–1.38) marginally worse in 2019 than in 2009."

Herbert W. Marsh 2023 (2)¶

Herbert W. Marsh, Jiesi Guo, Philip D. Parker, Reinhard Pekrun, Geetanjali Basarkod, Theresa Dicke, et al. (2023). Peer Victimization: an Integrative Review and Cross-National Test of a Tripartite Model. Educational Psychology Review. https://doi.org/10.1007/s10648-023-09765-x

q2 · i? · associational · r2

The review reports Ng et al.'s (2022) meta-analytic conclusion that intervention effects were "very small to small" and "marginally effective", with effects on victimization even weaker than those targeting bullying. No effect size is printed for this meta-analysis.

"Ng et al.’s (2022) meta-analysis similarly concluded that intervention effects were “very small to small” and that these “marginally effective” results were generally consistent with previous meta-analyses."

Discussion¶

Related Claims¶

• School-based anti-bullying programs reduce bullying perpetration and victimization globally — reports the opposite
• Program effectiveness varies by country: Greece led for perpetration, Italy for victimization — related
• Effectiveness of anti-bullying programs varies significantly across evaluations (heterogeneity) — related
• Regional differences in program effectiveness: North America led for perpetration, Scandinavia for victimization, with no clear overall pattern — related
• Funnel-plot asymmetry ran contrary to small-study effects because larger-sample studies reported larger effect sizes, likely reflecting longer training programs — related