“…Treatment of persons who committed sexual offenses focuses on the reduction of sexual recidivism in order to increase public safety. Although previous meta-analyses provided evidence for reductions in sexual recidivism ( Alexander, 1999 ; Aos et al, 2006 ; Furby et al, 1989 ; Gallagher et al, 1999 ; Gannon et al, 2019 ; Grossman et al, 1999 ; Hall, 1995 ; Hanson et al, 2002 , 2009a , 2009b ; Kim et al, 2016 ; Lösel & Schmucker, 2005 ; Mpofu et al, 2018 ; Polizzi et al, 1999 ; Reitzel & Carbonell, 2006 ; Schmucker & Lösel, 2015 , 2017 ; Ter Beek et al, 2018 ; Walker et al, 2004 ), there is still controversy about which sample characteristics, treatment variables, or methodological issues contribute most to the effectiveness of treatment ( Lösel, 2020 ). Sound treatment evaluation in this field is complicated by various concerns, such as the heterogeneity among persons with sexual offense histories in terms of pre-treatment risk of reoffending, variances between adults and juveniles, differences in treatment approaches, and deficits in study design assigning appropriate treatment and control groups ( Lösel & Schmucker, 2017 ).…”