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Stretching Beyond Limits

The Wechsler Intelligence Scale for Children®—Fourth Edition (WISC IV)

This scale identifies key cognitive strengths and weaknesses related to learning disabilities, executive function, attention disorders, intellectual disability, and giftedness. Administered between 65 and 80 minutes, the WISC-IV contains 10 core subtests and 5 additional subtests. These are summed to four indexes (the Verbal Comprehension Index, the Perceptual Reasoning Index, the Working Memory Index and the Processing Speed Index) and one Full Scale IQ (FSIQ) which ranges from lowest 40 to highest 160 points. Subtests are given for additional examination of processing abilities. The age range for this test is between 6 years and 16 years 11 months. 

Four index scores that are provided include:

• Verbal Comprehension Index (VCI)
• Perceptual Reasoning Index (PRI)
• Working Memory Index (WMI)
• Processing Speed Index (PSI)

The following shows the four main indexes of the WISC-IV and what they measure:


Verbal Comprehension Index (VCI) 

Measure: Verbal concept formation

It assesses children's 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. It can tap preferences for verbal information, a difficulty with novel and unexpected situations, or a desire for more time to process information rather than decide "on the spot." 
Note: This index is a good predictor of readiness for school and achievement orientation, but can be influenced by background, education, and cultural opportunities.


Perceptual Reasoning Index (PRI) 

Measure: Non-verbal and fluid reasoning. 

It assesses children's ability to examine a problem, draw upon visual-motor and visual-spatial skills, organize their thoughts, create solutions, and then test them. It can also tap preferences for visual information, comfort with novel and unexpected situations, or a preference to learn by doing.


Working Memory Index (WMI) 

Measure: Working memory. 

It assesses children's ability to memorize new information, hold it in short-term memory, concentrate, and manipulate that information to produce some result or reasoning processes. It is important in higher-order thinking, learning, and achievement. It can tap concentration, planning ability, cognitive flexibility, and sequencing skill, but is sensitive to anxiety too. It is an important component of learning and achievement, and ability to self-monitor.


Processing Speed Index (PSI) 

Measure: Processing speed. 

It assesses children's abilities to focus attention and quickly scan, discriminate between, and sequentially order visual information. It requires persistence and planning ability, but is sensitive to motivation, difficulty working under a time pressure, and motor coordination too. Cultural factors seem to have little impact on it. It is related to reading performance and development too. It is related to Working Memory in that increased processing speed can decrease the load placed on working memory, while decreased processing speed can impair the effectiveness of working memory.


Is Testing Important?

It really depends on why you need the test done. A few reasons to test:

• Tests can provide detailed information about your child’s learning needs. This would help parents and teachers to assess strengths and weaknesses
• To determine if the child is above or below average so an individualized educational programme (IEP) can be developed
• For Gifted &Talented Programme admissions
• Early interventions of learning differences – which helps in facilitating appropriate educational plan to meet needs of the child.  


In essence, a child should be tested to provide deeper understanding for parents and/or educators and to help them provide a better education to the child. The test scores can determine if the child will benefit from advanced or remedial classes.