The Wechsler Intelligence Scales - Research Paper Example

Currently, the scales are available in three versions, they include WAIS-III, which measures adult intelligence, WISC-III, which measures intelligence in children, and WPPSI-R, which is designed for children aged between 4 and 6 ? years (IUPUI, 2010). There have been several revisions to improve the test ability of the scales and to include more population groups since Wechsler published the first scale in 1939. The purpose of WAIS-III is to measure adult intellectual ability. The scale is in its third edition, and is designed for individuals aged between 16 and 89 years (Pearson Assessments, 2011).

The scale is administered in the form of visual, performance, and full tests for durations of between 60 and 90 minutes. The scale’s norms include IQ and index scores, which are all designed to test the individual’s intellectual ability in a comprehensive manner. The scale’s internal structure is composed of subtests that include tests on verbal comprehension, perceptual organization, working memory, processing speed and visual memory. The validity and reliability of WAIS-III are supported by correlations with previous editions of the intelligence scales and by clinical studies on adults with hearing impairments, retardation, and other forms of cognitive disabilities.

The scale’s validity and reliability are also promoted by the availability of multiple tests administered to people with multiple intellectual abilities. WISC-III Also developed by David Wechsler, the purpose of the third edition children’s intelligence scale, (WISC-III), is to test for verbal and performance abilities among children aged between 7 and 16 years. It includes tests on information, coding, arithmetic, vocabulary, and comprehension (Kamphaus, 2005). Verbal abilities are tested through oral subtests while performance abilities are tested through nonverbal problems.

Although all tests are timed, bonus points are awarded for faster work and older children have to earn much higher points to rank with the appropriate age group. The test has several subtests grouped into the general areas of verbal and performance scales. Verbal scales are designed to measure language, memory skills, reasoning and general knowledge while performance scales are meant to measure problem-solving, spatial, and sequencing skills. Administration of the test is done by trained examiners to individual examinees and a complex test material is usually required.

In scoring, the test scores are converted to standard scores and computed with a standard deviation of 3 and a mean score of 10. Scores in the subscales of verbal and performance areas are turned into IQ scores, and later summed to obtain the overall score. All scores obtained in the tests are normative with a standard deviation of 15 and a mean score of 100. The scores are then classified to indicate the individual’s class as follows: Beyond 130- gifted, 120-129- very high, 110-119- bright normal and 90-109- average (IUPUI, 2010).

Individuals who score 85-89 are considered low average, 70-84 are classed as borderline mental functioning, and scores below 50 indicate cases of mild, moderate, or severe retardation. The multiple tests incorporated within the intelligence