“…The program has a strong evidence base, with randomized control trials demonstrating significant decreases in bullying and victimization after nine months of implementation, particularly for younger children aged 7 to 12 years (e.g., Kärnä et al 2011a, b;Kärnä et al 2013). In addition, further studies outside of Finland are beginning to emerge, where equally positive results have been reported in the UK (Clarkson et al 2019;Hutchings and Clarkson 2015) and Italy (Nocentini and Menesini 2016). Furthermore, some studies have revealed additional positive side effects of the KiVa program, including a reduction in internalizing symptoms such as anxiety and depression Salmivalli and Poskiparta 2012;Williford et al 2012) Studies based on Finnish samples have not revealed any gender differences in terms of how effective the program is at reducing bullying and victimization; however, Hutchings and Clarkson (2015) reported gender differences in their sample of 748 9-11-year-old pupils from 17 schools in the UK.…”