Discrepancy between Subset Scores on the WISC-IV
By Inderbir Kaur Sandhu, Ph.D
My 9 year old son just took the WISC IV and the Stanford Binet
Intelligence Scale section for Quantitative Reasoning and scored the
Weschler Intelligence Scale for Children - fourth edition
Full Scale score: 104 Percentile = 61
Verbal Comprehension Composite 100 Percentile = 50
Perceptual Reasoning Composite 90 Percentile = 25
Working Memory Composite 113 Percentile = 81
Processing Speed Composite 112 Percentile = 79
Stanford Binet Intelligence Scale
Quantitative Reasoning 103 Percentile = 60
His school is telling me that he is not qualified for excel classes. I
do not understand their reasoning. I also feel there is a need for more
testing due to the big difference between PRI, VCI and WMI, PSI. Through
researching about this type of IQ test, I have found that when there is
a big difference between the four categories (verbal, perceptual,
working processing) that additional testing is needed. Am I correct?
Please help me help my son, who has lost interest in school and is
bored. He has been since K. I have been battling school for a while now.
This year they finally agreed to the above tests. I am a little
concerned that the psychologist who administered the test is his
PS: I have a meeting scheduled with the school's director of student
services, principal, reg. teacher, excel teacher, psychologist and excel
It is unclear on the kind of results you were expecting. Is your son
showing signs of superior intelligence in an area but is not reflected
in the scores? Based on the standard norms, his full scale IQ score is
in the average range (90-109). His WMI and PSI are in the above average
range; however brought down by his VCI and PRI scores.
It has been noticed that some of the Full Scale IQ scores on the WISC-IV
are excessively lowered by either VCI and PRI or WMI and PSI scores. Due
to the fact that intelligence is primarily abstract reasoning ability,
emphasis on short-term auditory memory and processing speed on
paper-and-pencil tests is less helpful.
In general the VCI is considered one of best predictors of overall
intelligence. Sometimes a low score occurs because the child has
acquired the information but does not have the expressive language to
demonstrate it. His WMI is high though which is the ability to
temporarily retain information in memory, perform some operation or
manipulation with it, and produce a result It also involves attention,
concentration, mental control, reasoning. This is an essential component
of other higher order cognitive processes and is closely related to
achievement and learning and frequently affected in learning disability.
He also showed high PSI which is the ability to quickly and correctly
scan, sequence, or discriminate simple visual information, short-term
visual memory; attention and visual-motor coordination. Therefore he is
showing clear strength in WMI and PSI and weakness in VCI and PRI.
You are right to suspect that the huge gap between the scores should
warrant for further testing. However, the GAI (General Ability Index)
should only be used in this case instead of the Full Scale IQ (FSIQ), if
the four composite scores vary by 23 or more points - which is not the
You indicated that your son is bored at school since preschool years but
did not indicate the reason. This has been going on for a while now;
perhaps there is another underlying concern that has not been attended
to. About the school psychologist, I believe even if there is some sort
on favouring or otherwise, the scores should not be too far off.
However, if you suspect something, it is best to speak to someone in
authority from the school. Do voice out your concern clearly and ask or
suggest what may be best for your son. If you are still unhappy, see an
educational psychologist who may be able to further test your son and
suggest suitable learning interventions to help him with his weak areas
and enhance his abilities. Good luck!