What is the Wechsler Intelligence Scale for children (WISC)?

Introduction

The Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) retains the essential content and structure of the original Wechsler Intelligence Scale for Children (WISC), published in 1949. The fourth edition, however, provides current representative normative data, updated test items that attempt to minimize culture bias and gender bias, more contemporary and visually appealing testing materials, and clearer administrative procedures, factor structure rules, and scoring rules. These improvements make the test more interesting and fairer for the child and more user-friendly for the examiner.

History of Development

David Wechsler
defined intelligence as the overall capacity of an individual to act purposefully, think rationally, and deal effectively with the environment. He believed intelligence to be a general concept that is multidetermined and multifaceted, rather than a specific trait or type of intellectual ability. An intelligence test is a device that assesses an individual’s potential for purposeful and useful behavior. To measure intelligence at the adult level, he selected eleven subtests from a wide range of existing standardized tests and published the Wechsler-Bellevue Intelligence Scale in 1939. This assessment became the Wechsler Adult Intelligence Scale in 1955 and is the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV), published in 2008 (the fifth edition was scheduled for publication in 2014).

In 1949, to provide an instrument to measure the intelligence of children as young as five years old, he developed the Wechsler Intelligence Scale for Children by designing easier items appropriate for children and adding them to the original scales. Due to suspected ethnic and socioeconomic bias in the standardization
sample, the test was revised in 1974 to establish normative data that were more representative of ethnic minorities and children from lower socioeconomic levels. The present form, the Wechsler Intelligence Scale for Children-Fourth Edition, was published in 2003.

Description of the Test

The WISC-IV consists of ten primary subtests and five supplementary subtests. There are four indexes to the test: Verbal Comprehension, Perceptual Reasoning, Working Memory, and Processing Speed. The verbal subtests assess the takers ability to listen to a question and to draw on knowledge to come to a conclusion and verbalize an answer. The Perpetual Reasoning Index stresses visualization, requiring the test taker to use motor and spatial skills to create and test solutions. The Working Memory Index tests the child's short-term memory and his or her ability to process the information. The Processing Speed Index assesses how quickly a child can order visual information. Each of these indexes is given a score to highlight the overall intellectual capabilities of the test taker. The results also produce a Full Scale IQ (FSIQ), which ranges score from 40 to 160.

Standardization, Reliability, and Validity

The WISC-IV was standardized on groups considered representative of the United States population of children according to 2000 census data. A stratified sampling plan was used to select children in representative proportions according to age, gender, race/ethnicity, geographic region, and parent education. A total of 2,200 children in eleven age groups ranging from six years to sixteen years, eleven months of age were selected, with an equal amount of male and female children in each group. Both public and private schools were sampled, and students receiving special services in school settings were included if they could speak and understand English. The test represented five levels of the children's parental education, and four US geographical areas.

Applications of the WISC-IV

The WISC-IV is commonly used for the psychoeducational assessment, neurological assessment, and clinical assessment of school-aged children. As a psychoeducational tool, the WISC-IV is often part of the assessment battery used for the diagnosis of intellectual disability and giftedness and for the appropriate placement in special school-based programs. Moreover, the separation of verbal and performance subtests allows the examiner to select portions of the test that can be successfully completed by children with hearing impairments, visual impairments, and orthopedic handicaps. Studies have shown that responses to WISC-IV subtests have provided information useful for the diagnosis and remediation of learning disabilities, brain injury, and other cognitive deficits.

Bibliography

Boyle, Gregory John, Gerald Matthews, and Donald H. Saklofske. Psychological Assessment. Los Angeles: Sage, 2012. Print.

Cohen, Ronald Jay, Mark E. Swerdlik, and Edward Sturman. Psychological Testing and Assessment: An Introduction to Tests and Measurement. New York: McGraw, 2013. Print.

Cooper, Shawn. The Clinical Use and Interpretation of the Wechsler Intelligence Scale for Children. 3rd ed. Springfield: Thomas, 1995. Print.

Groth-Marnat, Gary. Handbook of Psychological Assessment. 5th ed. New York: Wiley, 2009. Print.

Newmark, Charles S. Major Psychological Assessment Instruments. 2nd ed. Boston: Allyn, 1996. Print.

Raiford, Susan Engi, and Diane L. Coalson. Essentials of WPPSI-IV Assessment. Hoboken: Wiley, 2014. Print.

Sattler, Jerome M. Assessment of Children. 5th ed. San Diego: Author, 2006. Print.

Sattler, Jerome M. WISC-IV and WPPSI-R Supplement to Assessment of Children. San Diego: Author, 2004. Print.

Wechsler, David. Manual for the Wechsler Intelligence Scale for Children. 3rd ed. New York: Psychological Corporation, 1991. Print.

“The Wechsler Intelligence Scale for Children-Fourth Edition.” The Twelfth Mental Measurement Yearbook. Ed. Jane C. Conoley and James C. Impara. Lincoln: U of Nebraska P, 1995. Print.

Woodrich, David L. Children’s Psychological Testing: A Guide for Nonpsychologists. 3rd ed. Baltimore: Brookes, 1997. Print.