Given the propensity for clinical assessment of Attention-Deficit/Hyperactivity Disorder (ADHD) to focus on core behavioral symptoms, the current study examined how well other predictors classified children who were diagnosed with ADHD by licensed practitioners. Participants were 91 children (39 ADHD-identified, 52 without ADHD), aged 8 to 13 years. In addition to significantly more ADHD symptoms, the ADHD-identified group exhibited significantly more externalizing problems and internalizing symptoms, less adaptive functioning, and greater problem pervasiveness and severity. Binary logistic regression analyses indicated that problem pervasiveness and severity significantly predicted diagnostic group membership when controlling for other predictors, and pervasiveness added unique variance beyond measures of core ADHD symptoms. Diagnostic utility analyses showed measurement of problem pervasiveness and severity to be a useful tool in the identification of ADHD. Findings provide support for the practical use of a parent-report measure of impairment in the home as part of evidence-based assessment of ADHD.