IQ testing: The WISC-IV
By Inderbir Kaur Sandhu, Ph.D
I'm a new educational psychologist and have a couple of
questions about WISC IV assessments. Hope you can help!!
How soon after a child has been assessed can the WISC IV be
used again to reassess?
Also, I have heard that you have to administer the complete
WISC IV for it to be valid (i.e. that you can't use a few
subtest just to get an idea as you can with the BAS II). Is
A: Firstly, congratulations on
your new position! Hope this is not too late.
Ok, for readers not very familiar with the WISC IV (revised
in 2003), this is actually an updated version of the
previous test - the WISC III that tests IQs of children
between ages 6 and 16 years 11 months. This test consists of
10 core subtests with five additional subtests. All of these
are summed up to four indexes which makes the full scale IQ
(FSIQ) which ranges from 40 (lowest) to 160 (maximum score).
The WISC-IV indexes are the:
Verbal Comprehension Index (VCI)
Perceptual Reasoning Index (PRI)
Working Memory Index (WMI),
Processing Speed Index (PSI).
Testing time is between 65
to 80 minutes. More time would be required if additional
subtests are given; less time for children with Mental
As for your questions, a child tested on the WISC-III is
suggested to be reassessed after one year to avoid test
practice effect. This should be similar for the revised
version. It is however specified that if for some reason,
testing is divided into two sessions; the gap should not be
more than a week apart.
To get the FSIQ, you would need to administer the complete
test for it to be valid as that is how it has been
standardized and normed. You could do a few subtests to get
an idea for your on gauge on a child’s performance, but
validity would be questionable. You may want to do a
research on this - comparing results of a full test and
subtests for your own purpose if you feel that there would
be a strong correlation! Hope that helps and best of luck in