School Psychology Blog

The Wechsler Intelligence Scale for Children is referred to as the WISC. (No, not that type of whisk!) The WISC consists of a series of short sub tests that are used to assess cognitive ability. Usually the scores are consistent across the lifespan.

What is a WISC?

The WISC-IV (Wechsler Intelligence Scale for Children- Fourth Edition) is an individually administered clinical instrument for assessing cognitive ability of children between the ages of 6 years through to 16 years 11 months. The test provides subtest and composite scores which represent intellectual functioning in specific cognitive domains as well as a composite score which represents general intellectual ability. The WISC-IV takes from 1 ½ to 2 hours to complete. The report and scoring of results takes a qualified psychologist from 4 to 8 hours to complete.

Why might a teacher recommend a WISC Report?

A classroom teacher may recommend a WISC if there are inconsistencies in a child’s performance or a child is struggling to comprehend grade appropriate tasks.  The WISC assesses a student’s learning, potential and ability.  The WISC should be used as a part of a comprehensive psycho educational assessment. Often psychologists will use the WISC and an achievement based test, such as the WIAT–II (Wechsler Individual Achievement Test—Second Edition) to fully assess an individual’s learning profile.

Key Benefits of a WISC Assessment

The main benefits include:

• Early identification of reading & learning issues;
• Useful in identifying learning disabilities;
• Understanding of an individual’s learning profile;
• Identification of gifted children;
• The assessment also helps Schools make appropriate; accommodations and develop learning plans for individual students;
  and
• The ability to determine learning processes, which include both strengths and weaknesses and the impact that they might have on individual student performance.

How to make sense of a WISC report?

The WISC allows the psychologist to identify learning patterns. It has four main components that are referred to as Indexes. These are called the Verbal Comprehension Index, the Perceptual Reasoning Index, the Working Memory Index and the Processing Speed Index.  Within each of these four domains are a variety of subtests that form the index score.

1. The Verbal Comprehension Score emphasises crystallised intelligence and knowledge application.
2. The Perceptual Reasoning Scores related to fluid reasoning/ intelligence or the ability to learn new information.
3. The Working Memory Score assess auditory short term memory and retrieval.
4. The Processing Speed Index had a emphasis on mental quickness and task performance with focused concentration and attention.

Verbal Comprehension Index

Verbal Comprehension Index (VCI) – measures verbal concept formation, verbal reasoning, and knowledge acquired from one’s environment. The subtests include:

• Vocabulary: word knowledge and retrieval
• Similarities: Verbal concepts and reasoning
• Comprehension: social knowledge and awareness
• Information*:  recall of verbally-encoded, factual  information
• Word Reasoning*: general reasoning ability

Perceptual Reasoning Index

Perceptual Reasoning Index (PRI) – measures perceptual and fluid reasoning, spatial processing, and visual-motor integration.  The sub tests include:

• Block Design:  visual spatial reasoning and visual-constructional ability.
• Matrix Reasoning:  non verbal reasoning and concept formation.
• Picture Concepts:  abstract, categorical reasoning.
• Picture Completion:* attention to visual detail.

Working Memory Index

Working Memory Index (WMI) – requires working memory processes to manipulate orally presented verbal sequences. Or to simply recall orally presented sequential information. The sub tests include:

• Digit Span – Digits Forward: Auditory short-term memory.
• Digit Span – Digits Backward:  Auditory working memory.
• Letter-Number Sequencing:  shorter string lengths indicate memory – longer reflect auditory processing.
• Arithmetic:* auditory short-term memory, auditory working memory, fact retrieval.

Processing Speed Index

Processing Speed Index (PSI) – requires visual perception and organisation, visual scanning, and the ability to use hands and eyes together efficiently. The attention factor is two minutes. The sub tests include:

• Coding:  speed and accuracy (fine motor control); incidental learning.
• Symbol Search:  mental processing speed and accuracy.
• Cancellation*:  processing speed, visual selective attention, visual neglect, vigilance.

*supplemental (not included in full scale IQ score)

Reference: Wechsler, D. (2003). WISC – IV Australian Administration and Scoring Manual. Harcourt Assessment.

filed under: Learning Disabilities, Psychological Testing