Attention problems can pose a serious challenge to the academic progress of children and adolescents. Currently, there are several different assessment methods utilized in the clinical diagnosis of Attention-Deficit/Hyperactivity Disorder (ADHD). Subjective and objective assessment measures purport to be measuring similar constructs of inattention, hyperactivity, and impulsivity. The present study examines the degree of correlation between the constructs of attention problems, hyperactivity/impulsivity, and signal detection between the Conners' Continuous Performance Test II Version 5 (CPT II) and a parent-report measure of attention problems, hyperactivity/impulsivity, aggression, emotional problems, and learning problems in a general clinical population of children and adolescents. This study also measures the correlation between these measures and the Woodcock Johnson III Tests of Cognitive Abilities (WJ-III COG) Auditory Attention subtest. No significant correlations were found among the CPT II errors of omission score or commissions score and attention problems or hyperactivity/impulsivity. No significant correlations were found among attention problems or hyperactivity/impulsivity and CPT II Reaction Time (RT), variability, or attentiveness. No significant correlations were found among the CPT II errors of omission or commissions scores and emotional problems, aggression, or learning problems. No significant correlations were found among the CPT II errors of omission score, commissions score, or RT and the WJ-III COG Auditory Attention subtest. A significant negative correlation was found between the CPT II variability score and the WJ-III COG Auditory Attention subtest. A significant positive correlation was found between the CPT II attentiveness score and the WJ-III COG Auditory Attention subtest. No significant correlations were found among any of the parent measures of attention problems Auditory Attention subtest. In a canonical correlation analysis there were high loadings on attention problems and hyperactivity/impulsivity on the parent-measure set and on commission errors and RT on the CPT II set. A modest loading on the multiple imputation set was also found on aggression problems and the parent-measure set. These findings support the overall conclusion that the CPT II does not generally relate to the parent-report measures. These findings indicate that there is little meaningful relationship between these two measures, which clinically are both used to assess attention problems.