Hannah Gaffney|Maria M. Ttofi|David P. Farrington
Evaluating the effectiveness of school-bullying prevention programs: An updated meta-analytical review
University of Cambridge|University of Cambridge|University of Cambridge
comprehensive extensive systematic review metaanalysis effectiveness bullying prevention programs presented report updates earlier research conducted farrington ttofi 2009 systematic searches online databases ie web science psycharticles psychinfo embase dare eric google scholar scopus conducted primary studies published 2009 december 2016 searches also conducted unpublished reports included systematic review primary studies must 1 describe evaluation schoolbased antibullying program 2 utilize appropriate operational definition schoolbullying eg centers disease control prevention 2014 farrington 1993 olweus 1992 3 measure schoolbullying perpetration andor victimization behaviors using quantitative measures 4 use experimental quasiexperimental design adequate control group following systematic screening 20000 search results total 100 evaluations 103 independent effect sizes eligible inclusion metaanalysis effect sizes estimated studies used rct designs n 45 quasiexperiments n 44 effect sizes 14 effect sizes age cohort designs antibullying programs significantly reduce bullying perpetration random effects 1309 bullying victimization random effects 1244 results suggest antibullying programs reduce schoolbullying perpetration approximately 1920 ad schoolbullying victimization approximately 1516 effect sizes vary greatly across studies significant heterogeneity studies bullying perpetration bullying victimization outcomes anticipated given variability range moderators example methodological designs type program used place implementation analyses suggest publication bias either metaanalysis variability effect sizes across different methodological designs investigated primary studies employing age cohort designs n 14 provide largest effects reducing bullying perpetration 1474 victimization 1302 relation bullying victimization outcomes beforeafterexperimentalcontrol designs provide similar effects 1225 randomized controlled trials 121 randomized controlled trials 1244 effective reducing bullying perpetration beforeafterexperimentalcontrol designs 1187 future aim explain differences across programs correlating individual effect sizes varying program components varying methodological elements available across 100 evaluations