Confusion on IQ score
By Inderbir Kaur Sandhu, Ph.D
Q:
My child has been tested using the SB5 as having a FSIQ of
134. I am told this places him at or above the 99th
percentile. However I am a little confused as to whether all
IQ tests are all 'normed', by which I mean does the 99th
percentile give the same FSIQ number across all IQ tests?
I am asking the question because I am trying to advocate for
some differentiation of the curriculum for my son and am
confused about what terminology I should use and what I
trying to advocate for. My net searches have not made this
any clearer!! My son's school have told me he is
'moderately' gifted based on the FSIQ of 134 but another
teacher I spoke with suggested the SB5 was yielding lower
scores overall so I should focus instead on the percentile.
On the net I read that scores above the 99th percentile are
termed 'highly' gifted and that a score in the 99th
percentile would qualify him for Mensa, but equally on the
Mensa site it says they won't rely on IQ scores and instead
only look at percentiles. So how does a score of 134 equate
to scores on other tests (e.g. the Wecshler)? Any light you
can shed on this confusion would be most appreciated!
A: A score in the 99th
percentile is definitely a better indicator for comparison
for tests. This means that your child is in the top 1%.
However, different tests may yield different scores. Having
said that, scores on standardized intelligence tests are
rather highly correlated, that is, if one scores high on a
certain intelligence test, s/he should score equally high on
another test. All standardized tests are normed against a
large sample. The fact that they are accepted as
standardized measures assures us of its reliability and
validity.
A rough guide for comparison on the levels of giftedness is
as indicated below:
| |
Stanford-Binet 5 |
WISC
IV |
| Moderately Gifted |
120 - 129 |
130 - 138 |
| Highly Gifted |
125 - 135 |
138 - 145 |
| Exceptionally
Gifted |
130 - 140 |
145 - 152 |
| Profoundly Gifted |
135 - 141 and above |
152 - 160 |
The SB-5 and the WISC-III have a ceiling of 160. However,
the WISC-IV has 210 extended scale, with subtest ceilings of
up to 28 which would be suitable for children scoring at
ceiling levels. Your son scored 134, which places him in the
highly gifted category for the SB5 and moderately gifted for
the WISC-IV.
It is also true that children these days are scoring lower
as compared to the older tests (WISC III or the older SB).
Therefore, it has been recommended that a new set of scores
and descriptive levels of giftedness be used, which starts
at 120 to 125 for moderately gifted, and progressing to 142
to 145 and above for profoundly gifted. This is closer to
the scores for the SB5. So, your son is definitely gifted
based on the test score, he needs to be in a gifted program
to ensure maximum development. Hope that helps a little.
Good luck!
| 
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