Accurate assessment of bullying is essential to intervention planning and the evaluation of bullying prevention programs; however, assessment itself has been called the “Achilles’ heel” of bullying research (Cornell, Sheras, & Cole, 2006). Researchers worldwide have long struggled to defi ne and operationalize bullying in ways that facilitate cross-national comparisons and to accurately estimate the prevalence of bullying. Th ese eff orts have produced equivocal results with considerable diff erences in prevalence rates across studies (Smith et al., 1999), a fi nding that raises the issue of whether rates of bullying diff er dramatically across samples or if differences refl ect measurement imprecision. Other measurement concerns include variations in defi nitions and time frames used, whether or not to provide an a priori defi nition of bullying to respondents (Espelage & Swearer, 2003; Solberg & Olweus, 2003); whether to use self-report, peer nomination, or teacher report methods (Cornell et al. 2006; Solberg & Olweus, 2003); and whether currently used measures actually assess the subset of peer victimization that is intended to be captured by the scientifi c defi nition of bullying (Greif & Furlong, 2006).