(no teacher ratings were available for age 4). ADHD scores from the three raters were highly intercorrelated (p < .01). A composite score for ADHD symptoms was derived by summing the DISC–IV ADHD (lifetime) symptom count, the CBCL attention subscale score, and the TRF attention subscale, which were each first z-score transformed to provide uniform scaling. Likewise, we developed a composite score for conduct disorder symptoms by summing the DISC–IV conduct disorder (lifetime) symptom count, the CBCL externalizing subscale score, and the TRF externalizing subscale (as with the ADHD composite, conduct disorder scores from the three raters were also significantly intercorrelated, p < .01), which were z-score transformed prior to summing.
