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Technical terms in the WISC-IV

By Inderbir Kaur Sandhu, Ph.D

Q: My 9 year old ADHD son scored 97.5% for Perceptual Reasoning and 95.5 % Visual Perception, IQ 120. Although I went to Harvard, all the web info is so jargon laden that I have no real idea of what they are talking.

In layman's English, what are the general definitions that are not so mushy that they are bereft of meaning to simple folk ? I can not brag to my elite friends if I can't define the terms myself.

A: I have answered a number on queries regarding the score interpretation of the WISC-IV (I assume that this is the test version that your son took since it was not indicated), so I suggest that readers go through previous newsletters for more details on the test.

In this case, based on the FSIQ, your son should be in the bright category (please read the answer on " Stanford-Binet 5 Score Interpretation").

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), and

  • Processing Speed Index (PSI).

On individual scores, the following table may be helpful as a guide of average scores of children in the gifted.

Gifted Average 124.7 120.4 112.5 110.6 123.5

On the jargons, I hope the following details would help in understanding the test further. I will further explain some of the concepts in the subsets that may be a little more difficult to understand:

Verbal Comprehension Index (VCI)
A measure of verbal concept formation (core subtests include similarities, vocabularies and comprehension). Here, children are assessed based on their ability to listen to a question, draw upon learned information from both formal and informal education, reason through an answer, and express their thoughts aloud. This is indeed a good predictor of readiness for school and achievement orientation. Results can be influenced by background, education, and cultural opportunities.

Similarities: Designed to measure verbal reasoning and concept formation. It also involves auditory comprehension, memory, distinguishing non-essential and essential features, and verbal expression.

Perceptual Reasoning Index (PRI)
A measure of non-verbal and fluid reasoning – an ability to perform mental operations, such as the manipulation of abstract symbols (core subsets include block design, picture concept and matrix reasoning). Children are assessed based on their ability to examine a problem, draw upon visual-motor and visual-spatial skills, organize their thoughts, create solutions, and test them. This test enables tapping of preferential skills for visual information, comfort with novel and unexpected situations, or a preference to learn by doing.

Block design: Designed to measure the ability to analyze and synthesize abstract visual stimuli and nonverbal concept formation. It also involves visual perception and organization, visual-motor coordination, spatial visualization, learning, and the ability to separate figure and ground in visual stimuli.

Picture Concept: Designed to measure abstract, categorical reasoning ability. The child is presented with two or three rows of pictures and chooses one picture from each row to form a group with a common characteristic. Solutions to easier items are generally attained by reasoning based on concrete representations, and the solutions to more difficult items are obtained by reasoning based on more abstract representations.

Matrix reasoning: Measure of fluid intelligence and a reliable estimate of general intellectual ability. Four types of matrices include continuous and discrete pattern completion, classification, analogical reasoning, and serial reasoning.

Working Memory Index (WMI)
A measure of working memory (core subsets include digit span and letter number sequencing). Children are assessed based on their ability to memorize new information, hold it in short-term memory, concentrate, and manipulate that information to produce some result or reasoning processes. Results can tap on a child's level of concentration, planning ability, cognitive flexibility, and sequencing skill.

Digit Span: Digit Span Forward requires the child to repeat numbers in the same order as read aloud by the examiner, whereas Digit Span Backward requires the child to repeat the numbers in the reverse order of that presented by the examiner. The shift from the Digit Span Forward task to the Digit Span Backward task requires cognitive flexibility and mental alertness.

Letter number sequencing: The child is presented a series of numbers and letters. The child repeats numbers then letters in proper order. This involves sequencing, mental manipulation, attention, short-term auditory memory, visuospatial imaging, and processing speed.

Processing Speed Index (PSI)
A measure of processing speed (core subsets include coding and symbol search). Children are assessed based on their ability to focus attention and quickly scan, discriminate between, and sequentially order visual information. Persistence and planning ability is required here and is related to reading performance and development.

I hope the above has been helpful. Unfortunately, the above concepts are specific to the test, hence it is difficult to use simpler explanation terms as the meaning may be compromised with. It is also advisable to speak to your child's tester to see if s/he would be able to explain the scores better verbally. Good luck!

Featured Resource


Essentials of WISC-IV Assessment
Dawn P. Flanagan Ph.D, Alan S. Kaufman Ph.D

The WISC-IV is the top intelligence assessment instrument for children in the US, providing essential information into a child's cognitive functioning. This book applies a new, expanded theory-based approach to interpreting the latest edition of the WISCŪ and provides beginning and seasoned clinicians with comprehensive step-by-step guidelines to administering, scoring, and interpreting this latest revision of the Wechsler Intelligence Scale for Children.

This book provides students and practitioners with an unparalleled resource for learning and application, including expert assessment of the test's relative strengths and weaknesses, valuable advice on its clinical applications, and illuminating case reports.

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