Convergent and Discriminant Validity of Trait and Source Effects in ADHD-Inattention and Hyperactivity/Impulsivity Measures Across a 3-Month Interval

Confirmatory factor analysis was used to model a multitrait (ADHD-inattention and hyperactivity/ impulsivity) by multisource (teachers and parents) design across a 3-month interval in a sample of 360 Australian elementary school children. The purpose was to evaluate the convergent and discriminant validity of the ADHD-inattention (IN) and hyperactivity/impulsivity (H/I) measures. Although similar traits and similar sources showed stronger correlations across time than dissimilar traits and dissimilar sources, the amount of source variance in the ADHD-IN and ADHD-H/I measures was substantial and consistent across the interval (M D 59%; rangeD35–84%). This large amount of source variance raises the possibility that the correlations of the IN and H/I rating scales with other constructs (e.g., social competence, conduct problems) represent mostly source rather than trait effects. Multitrait by multisource analyses provide a means to answer this question and further advance understanding of ADHD. KEY WORDS