Wechsler Intelligence Scale for Children III 1
Literature Review on the Wechsler Intelligence Scale for Children III
Brittany Smith
Wake Forest University Fall 2013
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Abstract
The Wechsler Intelligence Scale for Children III (WISC III) is an individually
administered assessment designed for children between the ages of six and sixteen. The test was
created to measure the overall intellectual ability of adults and older adolescents. It is commonly
administered by school psychologists and other certified professionals in K-12 schools to
evaluate children and determine whether they qualify for Academically and Intellectually Gifted
(AIG)/Academically Gifted (AG) programs, or Exceptional Children status, for children who are
developmentally delayed. This literature review will highlight past and current usage of the
WISC III, the test’s long term stability, reliability, construct validity, and test limitations.
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Introduction
Dr. David Wechsler, a renowned clinical psychologist, developed several intelligence
tests for individuals of different age groups. Wechsler defined intelligence as the “capacity of
the individual to act purposefully, think rationally, and to deal effectively with the environment”
(Beal, 2004). The first Wechsler scale, formally entitled the Wechsler Bellevue Intelligence
Scale, Form 1, was introduced in 1939. The test was created to measure the overall intellectual
ability of adults and older adolescents. Ten years later, Dr. Wechsler’s first children’s ability
test, The Wechsler Intelligence Scale for Children, was published (Edelman, 1996). The
questions used in this assessment were mostly scaled down versions of the questions that were
included in the Wechsler Bellevue Intelligence Scale form II. Revisions to the WISC were made
in 1974, to mitigate cultural bias, which included adding more pictures representing African
Americans and women in the picture completion subtest portion.
Today, Wechsler instruments are frequently referenced in research, and various reports
on the use of these tests show that they are the most regularly used intelligence tests (Whiston,
2013). Research also shows that counselors often use Wechsler tests; for example, the WISCrevised edition (WISC-IV R) is the most commonly used assessment tool for school counselors.
Community mental health counselors also use these assessments, particularly the revised edition.
Due to the widespread use of these tests, counselors in various areas within the counseling field
should be familiar with them (Whiston, 2013).
The fourth edition of the WISC test was released in 2008, but due to a dearth of research
that I obtained on this version, this review will focus on the third edition. The Wechsler
Intelligence Scale for Children III (WISC III), is an individually administered assessment
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designed for children between the ages of six and sixteen (Edelman, 1996). Overall, many
significant changes were incorporated into the third edition of the WISC. For example, several
test questions were altered to lessen the ambiguity and to make the amount of male and female
gender items equal. Many of the gender revisions were made to the math section of the
assessment. The picture completion and picture arrangement sections of the test were also
changed, by adding more color to be more visually appealing. In addition to these changes, the
WISC III test manual gave a comprehensive description of the reliability and validity of the
assessment (Braden, 1991).
The WISC III is commonly administered by school psychologists and other certified
professionals in K-12 schools to evaluate children and determine whether they qualify for
Academically and Intellectually Gifted (AIG)/Academically gifted (AG) programs, or
Exceptional Children status, for children who are developmentally delayed (Canivez & Watkins,
1998). Some research has indicated that Wechsler intelligence scales may not sufficiently
evaluate individuals with extremely high or low levels of intelligence (IQ scores below 40 more
than 160). Regardless of whether or not this is true, the test is still used in evaluating children for
academically gifted programs, who may score above 160.
The WISC III includes thirteen subtests, which are divided into two specific scales,
verbal and performance (Braden, 1996). The sections of the assessment, in order of
administration, include the following: (1) picture completion, (2) information, (3) coding, (4)
similarities, (5) picture arrangement, (6) arithmetic, (7) block design, (8) vocabulary, (9) object
assembly, (10) comprehension, (11) symbol search (optional), (12) digit span (optional), (13)
mazes (optional). Out of the thirteen subtests in the WISC, six are verbal tests, which include
items that use language based items, while the remaining performance scale tests implement
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visual-motor items that require less language use. The WISC–III also has “four optional factorbased index scores (Verbal Comprehension Index [VCI], Perceptual Organization Index [POI],
Freedom From Distractibility Index [FDI], and Processing Speed Index [PSI])” (Canivez &
Watkins, 1998). Administrators of this assessment should be able to work well with children of
various ages, be well versed in test protocol, and be trained in the correct usage of the testing
instrument (Braden, 1991). They also should be knowledgeable of how to accurately interpret
the assessment results (Whiston, 2013).
Long term stability
In a general review of the WISC, Edelman (1996) indicated that since the WISC was first
used, the two scales of the test have continuously had internal consistency reliability coefficient
of .89 or higher. Test-retest reliability shows that there is a drastic practice effect on the
performance scales when individuals take the retest within twelve to sixty-three days after
initially taking it. This may be due to the fact that they remember specific test items or certain
problem solving strategies that were particularly helpful. As a result of them having recently
been exposed to the test questions, their performance IQ points typically increase from 11.5 to
13.5.
Canivez and Wakins (1998) researched the long term stability of the Wechsler
Intelligence Scale III with a sample of 667 students, who were all evaluated twice for exceptional
children/special education services. The age groups most represented in the sample were school
age children between the ages of six and twelve (180 students), and adolescents between thirteen
and seventeen (200 students). The mean test-retest interval was 2.87 years, and the test-retest
reliability coefficient for the verbal IQ, performance IQ, and full scale IQ were all between .87
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and .91. The average differences between the first and second administration of the test were not
statistically significant. Overall, the results of his study showed the greatest long term stability
for the results of WISC III that had been reported at the time this article was published.
On the contrary, in a study conducted by Cummins (2001), results showed that the
children who had learning disabilities showed notable variability in their performance on the
WISC over time, in comparison to the general population. Cummins conducted a study to
determine how consistent WISC scores would be for youth with identified learning disabilities.
According to this researcher, previous research showed that some children with learning
disabilities have less stability in their performance on the WISC over time than children who do
not have disabilities. The sample size for the study was 214 children who all had been diagnosed
with a learning disability. Test-retest reliability for results for the assessment were monitored
and calculated over the course of three years, by evaluating correlational and t-test data. Verbal
IQ, full scale IQ, and verbal index scores decreased considerably between the times that the tests
were administered. After analyzing the score distribution, Cummins concluded that children
with learning disabilities in this sample showed more instability in test-retest scores on the WISC
III than in the general population.
Construct validity
In a research study published in 2005, by Canivez, Nietzel, and Martin (2005), the
construct validity of the WISC III was compared to that of the Kaufman Brief Intelligence Test
(K-BIT), and the Adjustment Scales for Children and Adolescents (ASCA). 207 children and
adolescents in grades ranging from kindergarten to tenth grade were evaluated by evaluation
teams in schools for special education services. Out of the 207 students, 164 had an identifiable,
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diagnosed disability. Out of the 207, 118 (51%) had a learning disability, 23 (11.1%) were
mentally retarded, 15 (7.2%) had serious emotional disabilities, 6 (2.9%) had Attention deficit
hyperactivity disorder, 1 (0.5%) was autistic, and 1 (0.5%) had a serious emotional disability and
a learning disability. Researchers evaluated construct validity in the WISC and K-BIT tests by
observing converging and discriminant comparisons, and found that there were statistically
significant correlations between them. This confirmed that there is convergent validity in these
two tests.
Overall, the findings in the study showed that there is construct validity of the three
assessments. However, there were some limitations to this study that inhibit the generalizability
of the results to a greater population. The majority (190) of students involved in the study lived
in rural areas in Illinois, while the remaining seventeen were from Arizona. Not only was the
sample not geographically diverse, but the proportions of African American and Hispanic
American students in the study were lower than those in the US population (Canivez et al.,
2005).
Test Limitations
Though there were many changes made to improve the third edition of WISC, there are
still some areas that could be stronger. For example, research shows that the subtest stability did
not increase in this edition, and it may be worse than that of the WISC-Revised Edition (Braden,
1991). Also, Braden mentioned that some subtests give bonus points to for speed, which may
negatively affect the scores of children who do not respond as quickly to questions as others. In
addition, some critics of the WISC III claimed that the third edition should have been
restructured, but their opinions on exactly how the test should have been structured differ greatly.
For example, one critic believed that the test should reflect multiple intelligences, while another
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stated that the test should reflect a “singular, hierarchical cognitive model” (Braden, 1991).
Lastly, some researchers disapproved of Wechsler’s definition of intelligence, and held opposing
views on how it should be altered (Braden, 1991).
Conclusion
In spite of the critiques that have been made against the WISC III and its perceived
shortcomings, research shows that the test is highly effective in evaluating children’s level of
intelligence. As with any other fallible assessment measure, there are ways that it can be
improved, but overall, the benefits outweigh the weaknesses. Though the fourth edition is now
available, the WISC III continues to be used today by professionals.
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