Full Scale IQ Score
A measure of the child's global intellectual functioning (or g) is derived from the composite of subtests administered on the Wechsler. Full Scale IQ scores between 90 and 109 are considered Average. 110-119 is High Average; 120-129 Superior; and 130+ Very Superior. On the other side, scores of 80-89 are Low Average, 70-79 Borderline; and <69 Intellectually Deficient. The Full Scale IQ score has been researched for decades, and appears significantly related to academic achievement, occupational level, and educational attainment.
Verbal and Performance IQ Scores
The next step in interpreting the Wechsler report is to look at the Verbal and Performance IQ scores. VIQ is comprised of results of the Wechsler subtests that measure verbal comprehension. PIQ includes the Wechsler subtests that measure perceptual organization. While not entirely free of verbal ability, the performance IQ is generally a measure of non-verbal intellectual abilities.
Most LD children, and many non-LD children, will exhibit a discrepancy between the Verbal and Performance IQ scores. When a discrepancy of at least 12 points is found between the VIQ and PIQ, the Full Scale IQ score should be interpreted cautiously. Though the Verbal-Performance discrepancy is not used to diagnose a learning disability, it alerts parents and teachers to the child's strengths and weaknesses and should lead to an analysis of the individual subtests that comprise each score.
The WISC-III subtest scores range from 1-19 with 10 as the average score. Look at each subtest score and initially identify any subtest scores that are higher or lower than 10. This is your first clue to your child's intellectual strengths and weaknesses. The assessment report will note any subtests that are significant strengths and weaknesses in your child's profile. Statistical significance is a vital diagnostic tool on the WISC-III. Subtest score variances that are not statistically significant may be due to chance variation, and they should be considered only possible areas of strength and weakness to investigate further. Compare the significant subtest strengths and weaknesses with the following chart to learn the intellectual tasks and abilities that underly each subtest.