“…First, some studies examined children with various physical disabilities (Ju et al, 2006;Watson & Keith, 2002), intellectual disabilities (Ikeda et al, 2014;Zwicker et al, 2013) or both (present study; Edwards et al, 2003) while one study examined students with chronic illnesses without providing specific information regarding the type or the severity of the illness (Gkoltsiou et al, 2008). Second, the use of the parent-proxy version of the questionnaire might have resulted in lower HRQOL scores than those reported by the children themselves (Achenbach, McConaughy, & Howell, 1987;Jelsma & Ramma, 2010). However, using self-report measures, some researchers have reported differences between those two groups (Edwards et al, 2003;Ikeda et al, 2014;Watson & Keith, 2002;Zwicker et al, 2013) but others have found the opposite (Jelsma & Ramma, 2010;Ju et al, 2006;King et al, 1993).…”