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symptoms and whether they occur rarely, occasionally, pretty often, or very often; a child is considered to display a particular symptom only if the parent indicates that it occurs pretty often or very often, and diagnoses are made according to whether the child demonstrates the minimum number of symptoms specified in the DSM-IV for the disorder. High levels of interrater agreement (> 98%) on diagnoses of Oppositional Defiant Disorder using the DSM-III-R criteria in an identical structured format have been found (McNeil et al., 1991; Schuhmann et al., 1998). Interrater reliability was assessed for this measure by comparing the interview checklist data collected by the primary interviewer with that generated by an independent observer (an undergraduate assistant). The assistant scored the interview from a videotape. Interrater agreement was calculated by dividing the number of agreements by the number of agreements plus disagreements. Agreement was defined as exact correspondence between the two observers on binary decisions (e.g., has the duration of problem behavior been at least 6 months?) and as both observers scoring the occurrence of individual symptoms as present (i.e., rated as occurring pretty often or very often) or absent (i.e., rated as occurring rarely or occasionally). According to the above definition, interrater reliability was calculated as 100% on diagnoses of Oppositional Defiant Disorder. Peabody Picture Vocabulary Test --Revised (PPVT-R: Dunn & Dunn, 1981)
The PPVT-R is a measure of receptive vocabulary for American Standard English. The PPVT-R has two forms, L and M, which each contain 175 items. The measure is individually administered to participants who are asked to select verbally or non-verbally the picture that best represents each test item verbally presented by the examiner. The