WECHSLER INTELLIGENCE SCALE FOR CHILDREN - 4TH EDITION

WISC-IV

It is an individually administered clinical instrument for assessing the cognitive ability of children
aged 6 years through 16 years 11 months.

WISC IV has 4 composite scores (instead of the 2 we had with the WISC III).
Full Scale IQ (FSIQ) is comprises of the four composite scores.

WISC-IV Composite scores
  1. Verbal Comprehension Index (VCI)
  2. Perceptual Reasoning Index (PRI)
  3. Working Memory Index (WMI)
  4. Processing Speed Index (PSI)

 lThe diagram is from  Radford University, Department of Psychology, WISC-IV presentation

List of the Subtest under each of the four Indexes:
(key= "(  )" indicated that the subtest is not included in the index total score.)

Verbal Comprehension Index (VCI)
:
Requires verbal conceptualization, stored knowledge access and oral expression.  Orally presented questions that assess common-sense reasoning, reasoning out or retrieving word associations, and the ability to describe the nature or meaning of words.  Knowledge acquired from one's environment.  Verbal expression required (length of response varies).  One of the best predictors of overall intelligence.
  1. lSimilarities
  2. lVocabulary
  3. lComprehensionl
  4. (Information)
  5. l(Word Reasoning)
lPerceptual Reasoning Index (PRI): Requires visual perception, organization and reasoning with visually presented, nonverbal material to solve the kinds of problems that are NOT school taught.
The Block design also requires spatial processing, visual-motor coordination and the ability to apply all skills in a quick, efficient manner. The highest scores reflect both accurate and very quick responses.
Picture Concepts score may differ from these other subtest because of the effect of language on the performance.
  1. lBlock Design
  2. lPicture Concepts
  3. lMatrix Reasoning
  4. l(Picture Completion)

lWorking Memory Index (WMI): Requires working memory processes applied to the manipulation of orally presented verbal sequences.  THe ability to temporarily retain information in memory, by performing some operation or manipulation with it, and produce a result.  Involves attention, concentration, mental control, reasoning.  Essential component of other cognitive higher order progresses.   Closely related to achievement  and  learning (LD students frequently affected).
  1. lDigit Span
  2. lLetter-Number Sequencing
  3. l(Arithmetic)
lProcessing Speed Index (PSI): Requires visual perception and organization, visual scanning, and the efficient production of multiple motor responses.  These tasks require executive control of attention and sustained effort for a 2-minute period of time while working with simple visual material as quickly as possible.  Performance on Coding is also dependent on paired-associative learning.
  1. lCoding
  2. lSymbol Search
  3. l(Cancellation)
The WISC-IV has a total of 15 subtests, 10 are retained from the WISC-III
These are the five new subtests:
      1. Word Reasoning
      2. Matrix Reasoning
      3. Letter-Name Sequencing
      4. Symbol Search
      5. Cancellation
Object Assembly subtest from the WISC III is gone.
 
On the WISC III there was Picture Arrangement, now on the WISC IV there is Picture Concepts, under Perceptual Reasoning Index.  (Not sure if it is testing the same type of information or not.  Not to be confused with the Picture Completion is on both versions of the WISC).

I know that parents of child with NVLD were concerned about the loosing these two subtests:
Object Assembly and the Picture arrangement.

Schwab Learning website, parent to parent section:
WISC-III  OR  WISC-IV? Opinions?

From the test publisher website:
         
WISC-IV Frequently Asked Questions (FAQs)  
    

Scoring:

Current reports show that most students re-tested with the WISC-IV will have approximately a 5 point discrepancy, lower (to the negative) because of this newer version of WISC, its novelty and its increased difficulty.

The good news is that the WISC IV has been normed on normal peers and for special education populations:
Mental Retardation (MR), Attention-Deficit / Hyperactivity Disorder (AD/HD), Learning Disabilities (LD), both AD/HD and LD, Traumatic Brain Injury (TBI), etc.


With 4 composite scores (vs. 2 as is the case with the WISC III), there is no standard discrepancy formula, it now all has to be evaluated in terms of the child's ability, test results, current educational functioning, achievement test expectations based on ability, evaluation of the subtests as well as evaluation of the composite sets.

Some evaluators have suggested that a 19 point discrepancy in the VCI/PRI composites may warrant further investigation.
Standard deviation is 15 points, it is not clear that these score will tell enough about the child's areas of weakness.

The information on this was adapted from WISC IV presentations attended, parent discussions and emails.

WISC-IV by Wechsler, D. (2003), The Psychological Corporation, and
Dr. Donna R. Smith Power Point presentation, of the Harcourt Assessment, Inc. Publisher.


For more information  please visit these other websites:


Fairleigh Dickinson University, website created by Dumont/Willis

Pearson, Inc, WISC IV test

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Concord SPED PAC webpages, created March 28, 2004, by Melody Orfei
Webpage last modified on March 8, 2011 - V9, by Melody Orfei
mel3sons@gmail.com