The Wechsler Adult Intelligence Scale-IV (WAIS-IV) is an important, well accepted measure of intelligence in adults and adolescents above the age of 16. It is considered a gold standard intelligence test. Its advantages include that it is widely accepted and carefully normed and validated. It provides overall scores, but also a number of subscale scores to better identify the types of capabilities of the individual. The WAIS-IV is difficult and time consuming to administer, and scoring the assessment is also not necessarily easy. Reliability and validity of the WAIS-IV ranges from very good to excellent.
Description of Test
The WAIS-IV consists of ten core and five supplemental subtests. The results of the core subtests contribute to the Full Scale IQ measure. The test generates four index scores, each of which corresponds to a different type of intelligence. These are verbal comprehension index (VCI), perceptual reasoning index (PRI), working memory index (WMI), and processing speed index (PSI). In addition, two broadly based scores assess the individual’s overall intellectual capabilities in the Full Scale IQ ( a combination of the four indexes mentioned above) and the General Ability Index ( which is based only on the VRI and PRI (Canivez, 2008). Estimated administration time for the full WAIS-IV is less than two hours (Schraw, 2008).
Development of Test
The WAIS-IV was normalized using 2200 U.S. individuals in the age range of 16 to 90 which were closely matched to the demographics of the 2000 U.S. census for the general population. This normalizing sample was later extended by adding nearly 700 Canadians within that age range (Schraw, 2008). The median Full Scale IQ, as is traditional, is normalized to 100 with a standard deviation of 15. Goals for this version of the WAIS included updating the theoretical foundations, improving the psychometric capabilities, increasing the appropriateness of the measure for different developmental levels, improved usability, and increasing it’s usefulness in clinical conditions (Hartman, 2009). In particular, the WAIS-IV uses a more hierarchical theoretical foundation, one that is based on more than half a century of support, meaning, that that assessment is on even stronger theoretical foundations than ever before (Schraw, 2008).
In terms of validity and reliability, the stated coefficients for the testing range from good to excellent in all cases (Schraw, 2008), with typical coefficients in the 0.80 range. Benson et al. (2010) analyzed the measurement factors of the WAIS-IV and concluded that there is evidence to support the claim that the WAIS-IV measures the same intelligence constructs in individuals across the span of the age range for the assessment (Benson, 2010).
Assessment of Test
The WAIS-IV has several advantages over other intelligence tests. The theoretical foundation for the WAIS-IV is strong and widely accepted in cognitive science. Another advantage is that its multiple subtests provide a spectrum of analysis of the individual’s overall cognitive abilities. The WAIS-IV offers extensive information about the norming methodologies providing assurance of the overall reliability and validity of the assessment tool (Schraw, 2008). On the other hand it takes a long time to administer and scoring the test is not easy. It does not provide a fast immediate diagnosis in clinical situations where the time spent with the patient is limited to a few minutes t a time. It has also been criticized for too much of an academic focus without acknowledging social, artistic or other types of intelligence (Schraw, 2008).
Benson, N., Hulac, D. M., Kranzler, J. H. (2010). Independent examination of the Wechsler Adult Intelligence Scale—Fourth edition (WAIS-IV): What does the WAIS-IV measure? Psychological Assessment, 22 (1), 121-130.
Canivez, G. L. (2008). Wechsler Adult Intelligence Scale—Fourth Edition. Mental Measurements Yearbook, 18.
Hartman, D. E. (2009). Wechsler Adult Intelligence Scale IV (WAIS IV): Returne of the gold standard. Applied Neuropsychology, 16 (1), 85-87.
Schraw, G. (2008). Review of the Wechsler Adult Intelligence Scale-Fourth Edition. Mental Measurements Yearbook,18.