The Wechsler Intelligence Scale for Children-Fourth Edition
The Wechsler Intelligence Scale for Children-Fourth Edition, or WISC-IV as it is commonly known, is the most recent version of the popular individualized assessment instrument that is frequently used as part of evaluations for identification of special education populations like learning disabled students and students with mild mental disabilities. In addition to a Full Scale Intelligence Quotient, this test provides a wealth of information about strengths and weaknesses as well as learning styles. Unfortunately, school resources are often not available to provide this type of individualized assessment for gifted children even though results can be valuable for educational planning.
The WISC-IV is a standardized measure comprised of fifteen subtests (ten core and five supplemental/optional). This instrument provides a Full Scale Intelligence Quotient (FSIQ) and four Composite or Index Scores. Scores are provided as standard scores with a mean of 100 and a standard deviation of 15, meaning approximately two-thirds of the general population will obtain a Full Scale IQ Score between 85 and 115 on the WISC-IV.
- The Verbal Comprehension Index (VCI) Composite Score taps into verbal memory and reasoning skills and is derived from three subtests.
- The Perceptual Reasoning Index (PRI) Composite Score measures visual information processing and non-verbal reasoning and is derived from three subtests.
- The Working Memory Index (WMI) Composite Score is derived from the scores of two subtests that have attention and concentration components.
- The Processing Speed Index (PSI) Composite Score is derived from the scores of two paper-and-pencil subtests that require quick mental processing.
- The Full Scale IQ Score is a composite of the ten core subtests, taking into account skills in perceptual reasoning, verbal comprehension, working memory, and processing speed.
- Certain substitutions are allowed for any subtest that is improperly administered, "spoiled" for any reason, or not administered due to a disability. A maximum of two substitutions is allowed to derive a valid FSIQ (no more than one per Index), and subtests cannot be substituted arbitrarily.