Frequency of Verbal and Performance IQ Discrepancies on the WPPSI-R at Various Levels of Ability

Abstract

The issue of Verbal-Performance IQ discrepancy has been investigated with the Wechsler Preschool and Primary Scale of Intelligence (Wechsler, 1967) and, given the recent revision of this scale (WPPSIR; Wechsler, 1989), determining the average expectable scatter would be useful for the clinician. The present study examined the incidence of VIQ-PIQ discrepancies and subtest variation by ability level in the standardization sample of the WPPSIR. Cumulative frequency distributions were constructed for the overall sample of 1,700 children and for five ability levels (<79, 80-89, 90-109, 110-119, and 120+) within this sample. The average PIQ > VIQ was 11.54 points (SD = 9.10) and the average VIQ > PIQ was 10.69 (SD = 7.87). The average difference tended to increase with ability level. Subtest scatter also was examined and found to increase with ability level. These results are consistent with previous studies on both the WPPSI and the WISC-R.