Differential Relationships Between WISC-IV and WIAT-II Scales: An Evaluation of Potentially Moderating Child Demographics

Considerable debate exists regarding the accuracy of intelligence tests with members of different groups. This study investigated differential predictive validity of the Wechsler Intelligence Scale for Children–Fourth Edition. Participants from the WISC-IV–WIAT-II standardization linking sample (N = 550) ranged in age from 6 through 16 years (M = 11.6, SD = 3.2) and varied by the demographic variables of gender, race/ethnicity (Caucasian, African American, and Hispanic), and parent education level (8-11, 12, 13-15, and 16 years). Full Scale IQ and General Ability Index scores from the WISC-IV were used to predict scores on Mathematics, Oral Language, Reading, Written Language, and the total composite on the Wechsler Individual Achievement Test–Second Edition. Differences in prediction were evaluated between demographic subgroups via Potthoff’s technique. Of the 30 simultaneous tests, 25 revealed no statistically significant between group differences. The remaining statistically significant differences were found to have little practical or clinical influence when effect size estimates were considered. Results are discussed in the context of other ability measures that were previously investigated for differential validity as well as educational implications for clinicians.