Discrepancy Between Verbal And Non-Verbal Scores On The K-BIT 2
By Inderbir Kaur Sandhu, Ph.D
Q: We firmly believe our daughter is ADHD
but last year her school teacher and counselor rejected the idea because
she does not struggle academically. She was 7 yrs old and in first grade
when we requested she be tested to see if she was gifted because there
are children that are gifted that do actually have ADHD. She was in a
special advanced reading class and does very well with math.
A few days later the counselor did a K-BIT 2 test on her and mailed us
the results. Her scores were: Verbal SS = 128, Matrices SS = 105,
Composite IQ = 119. She was 7 yrs 2 mo on the test date. In the
explanation of her scores it states that her score of 119 placed her at
the 90th percentile rank meaning of 100 students her age she scored
better than 90% of them. But then went on to explain "Verbal test score
(128) and Nonverbal subtest (105) score were significantly different
(<.01). A few more lines into the letter it states we need to monitor
her progress in the classroom to be sure her visual problem solving
continues to develop. "(Please understand, however, that her score of
105 is solidly in the average range. It is just significantly lower than
her verbal ability score.)
What I would like to know is what the significant difference in scores
really means. I am really just trying to find some insight into why her
scores are so far apart and what that may mean for her in the future.
Firstly, just a brief explanation about the subtests for each on the
KBIT-2. Both subtests that make up the verbal score measure verbal
skills by assessing a person's knowledge of word meanings. Additionally,
the verbal tasks measure the child's verbal concept formation, reasoning
ability, and range of general information. The verbal score measures the
Broad Ability known as Crystallized Ability, which reflects the amount
of specific knowledge that a person has acquired within a culture and
the person's ability to apply this knowledge effectively. The nonverbal
score measures the person's ability to solve novel problems, those that
are not specifically taught or trained. To solve the problems presented
in the matrices subtest, the examinee needs to perceive various
attributes in the pictures, generate hypotheses about how the pictures
go together, and test out the hypotheses to arrive at a solution. Thus,
the matrices subtest measures Fluid Reasoning and Visual Processing.
It clearly appears that your daughter has trouble with the measures of
fluid reasoning and visual processing. The large discrepancy usually
indicates a nonverbal learning difficulty.
The Composite IQ score (also known as Full Scale in some tests) is based
on all or most of the subtests that is being tested. This is frequently
the number most people refer to when discussing someone's IQ. Experts
who develop intelligence tests use mathematical calculations to find the
mean or average score. An IQ score from 90 to 110 is generally
considered in the average range, corresponding to roughly 50 per cent of
the population. The higher the IQ score, the lesser the percentage. For
example, high scores of say 130 would only see about 2-3 per cent of the
population. A higher score of 145 should occur in about 0.1 per cent of
the time or once in a 1,000. Most gifted programs have a cut-off score
around the 97th percentile. This would mean a standard score of 128.
Based on a mean of 100 and standard deviation of 15, your daughter
scored in the average range (about 115-130 should be within the average
range on a bell curve) for the K-BIT-2. The cut-off for a gifted
education programme is usually 125-130 (your daughter scored 119) but
can be on a case-by-case basis since there may be a diagnosis of a
learning difficulty. You may need to see the tester to get the test
interpreted in detail to be able to determine her weaker areas and get
some help there.
The Kaufman Brief Intelligence Test (K-BIT) by definition is a “brief”
intelligence test, also known as a test used for "screening" children.
This means, the K-BIT2 test is just a few subtests of their KTEA (full
version). Therefore, if those subtests are not the child's strongest
areas, then the score could be quite different from the same child's
score on the comparable “full” assessment. Having said that, test
designers do select suitable subtests to include in a brief scale. This
is not done randomly, rather using good research background.
One caution for you daughter especially if you believe that she may have
ADHD; research has indicated that the Wechsler Abbreviated Scale of
Intelligence (WASI) showed more stable measure of ADHD children's
intelligence and that the KBIT-2 vocabulary scores were significantly
lower than the WASI verbal score, and that there was a significant
variability within the participants.
I would strongly suggest that you seek a second opinion if you wish for
your daughter to be enrolled in a programme catered to her needs, as one
brief test alone is insufficient to make diagnosis and decisions on her
learning ability. Wishing you all the best in this journey!