“…Based on research using community samples, evidence suggests that 70-80% of children have hit a sibling or engaged in at least mild sibling aggression, while approximately 30% of children have been “assaulted” by a sibling (Finkelhor, 2005; Miller, Grabell, Thomas, Bermann, & Graham-Bermann, 2012; Straus, Gelles, & Steinmetz, 1980). Definitions of sibling aggression vary from including only more severe forms of physical aggression such as “beating up” or using a weapon against a sibling, to separately examining rationally-derived subscales of mild and severe sibling aggression, to including all forms of child aggression against a sibling in a single scale (Eriksen & Jensen, 2009; Finkelhor, 2005; Miller et al, 2012). Several studies of sibling aggression exclude verbal aggression, focusing only on physical aggression, despite evidence that verbal aggression within a family is associated with negative child outcomes (Kolko, Kazdin, & Day, 1996; Teicher, Samson, Polcari, & McGreenery, 2006; Vissing, Straus, Gelles, & Harrop, 1991).…”