WAIS Psychological Test

I. Test Identification or Test name 

The Wechsler Adult Intelligence Scale also known as WAIS psychological test is an IQ test devised to measure cognitive ability and intelligence among older adolescents and adults. The original WAIS published in 1955 by David Wechsler was a revision of the Weschler-Bellevue Intelligence Scale previously developed in 1939. The latter tests were innovative during the 1930s as they incorporated tasks established for nonclinical purposes for use as a ‘clinical test battery”. The Form I achieved widespread popularity by the 1960s due to its incorporation of non-verbal and verbal items for all test takers. The former was known as performance scales. As previously mentioned, the integral purpose of this psychological test was to measure the intelligence of an individual as per the definition of the concept provided by the creator. Wechsler recognizes intelligence as the “global capacity of an individual to act purposefully, think rationally, and deal effectively with his environment”. In this regard, the author identified that human intelligence as one composed of specific elements that though not exclusively independent, are all interrelated and can be measured individually. 

The primary use of the test was to measure human intelligence in terms of verbal and performance skills in the context of personality. It is also a tool for clinical practice that helps make inferences of personality and pathology through the particular answers and patterns of subtest scores. In this regard, it is a useful measure for neuropsychological evaluation particularly in brain dysfunction (Rosenberg, McDonald, Rosenberg, & Westbrook, 2016). Significant differences shown in verbal and non-verbal intelligence will help clinicians identify the specific part of the brain that is damaged. Additionally, the WAIS can be a useful item for conducting diagnosis of various mental illnesses. For instance, intelligence quotient can help identify the mental retardation, attention-deficit/hyperactivity disorder (ADHD), and specific learning disabilities. 

II. Test Description and Format 

A. Sub-Scales 

The fourth edition of the WAIS test includes four major indexes including verbal comprehension, perceptual reasoning, working memory, and processing speed which represent the major components of intelligence. Each index includes various subtests used to measure a specific form of intelligence in the individual. The verbal comprehension and perception reasoning indexes determine degree of reasoning which is a key component of intelligence. On the other hand, Working Memory and Processing Speed Indexes measure mental efficiency. 

The first major index is the verbal comprehension (VCI), which includes four different tests; similarities, vocabulary, information, and comprehension. The first three are the integral or core factors of verbal reasoning with the latter being a supplemental intelligence. The Similarities subscale is used to measure semantic knowledge and abstract verbal reasoning where open-ended questions test the participant’s ability to describe similarities between two given concepts or words. The vocabulary subscale also tests semantic knowledge by measuring the degree of learning, comprehending, and being able to verbally express vocabulary. This test involves the use of cards with pictures where the participants names the object or defines the presented words. The information subscale evaluates the degree of general information an individual acquired from cultural interaction. Open-ended questions are used to ascertain of this intelligence. The comprehension subscale is a supplemental test for determining a person’s ability to deal with abstract social conventions, rules, and expressions that are common within the society. 

The perceptual reasoning index (PCI) is another means of evaluating the level of intelligence an individual has using five tests: block design, matrix reasoning, visual puzzles, picture completion, and figure weights. The last two subtests are considered supplemental intelligence in this category with the others forming the core. The block design test helps identify abilities in visual abstract processing, spatial perception, visual motor construction, and problem solving. In this regard, bi-colored blocks are used as the participants attempt to duplicate an image or model design (van Ool et al., 2017). The matrix-reasoning subtest incorporates measures to determine the individual’s abilities in nonverbal abstract problem solving, spatial reasoning, and inductive reasoning. The participant is asked to complete a grid by selecting the missing piece from options provided. The third subscale is the picture concepts or visual puzzles that measures nonverbal, categorical, and fluid forms of reasoning (Kaplan & Saccuzzo, 2017). They are identified by selecting pictures from a row of two or three objects that share common traits. Picture completion and figure weights are supplemental intelligence in PCI that test ability to perceive quickly visual details and quantitative and analogical reasoning respectively. 

The working memory index (WMI) attempts to measure the efficiency of the brain using three primary tests. The digit span assesses the individual’s abilities in attention, working memory, auditory processing, and attention. In this case, the participant is required to recall a series of numbers in order. The arithmetic test another core factor in WMI intelligence tests the individual’s ability to concentrate while conducting mental manipulation of mathematical problems (Kaplan & Saccuzzo, 2017). The participant undertakes division, multiplication, addition or subtraction problems. The final test is the letter-number sequencing a supplemental intelligence in this category. It evaluates the attention, working memory, and mental control. In this case, the participant should recall numbers in an increasing order and the letters in alphabetical order. 

The final index for measuring intelligence is the processing speed (PSI). It incorporates two major tests and one supplemental. PSI requires visual perception, organization, hand-eye coordination, and visual scanning (Canivez, 2013). In this case, it is essential to focus attention and scan quickly while discriminating and ordering visual information (Kaplan & Saccuzzo, 2017). The symbol search test evaluates the individual’s visual perception and recognition, concentration and attention, and mental speed and accuracy of processing images. Another integral test is coding involving fine motor control to achieve speed and accuracy, visual-motor dexterity, incidental learning, and nonverbal short-term memory. Cancellation is the supplemental test that assesses the visual perceptual speed of processing information, visual neglect and vigilance, and selective attention to particular visual information (Alexander, & Liljequist, 2016). The above tests are closely associated with working memory as a decrease in processing speed can have adverse effects on the processes of the working memory. 

B. Scoring System 

The WAIS-IV is the latest version of the psychological test that incorporates numerous techniques of scoring. In this new version of measuring intelligence, the test battery transitioned from a dual IQ system to an index score structure to ensure consistency with Wechsler Preschool and Primary Scale of Intelligence (WPPSI-III) and Wechsler Intelligence Scale for Children (WISC-IV). The structure provides an assessment for both Full Scale Intelligence Quotient (FSIQ) and fewer subtests in the four index scores including VCI, PRI, WMI, and PSI (van Ool et al., 2017). The test battery also includes scores for General Ability Index (GAI) that is drawn from the verbal comprehension and perceptual reasoning subtests to give an estimate of general intellectual ability, with condensed importance on the working memory and processing speed. 

The Wechsler intelligence scales are noted for lack of compatibility with individuals of extreme ends of intelligence quotients (above 160 and below 40). The author actually points out that the scale would be inappropriate for individuals below 70 or above 130 in IQ levels (Kaplan & Saccuzzo, 2017). It also evident that extreme caution should be taken when administering the tests to individuals at extreme age range (below 20 and above 70 years). As mentioned earlier, the WAIS psychological test yields score results on the full-scale IQ and the four indexes grouped into verbal and performance IQs (van Ool et al., 2017). The WAIS-IV was standardized on a sample of 2,200 individuals between the ages of 16 and 90 years all in the US (Kaplan & Saccuzzo, 2017). Through this practice, it was evident that the median FSIQ score was at 100 with a standard deviation of 15. Therefore, one score higher gives an IQ of 115 and one score lower gives an IQ of 85. A similar standardization extended on 688 Canadians within the same age range and provided a similar median raw score. 

The FSIQ score is derived from the combined performance of the VCI, PRI, WMI, and PSI, which include a total of 10 core subtests and 5 supplemental subtests. In this regard, the FSIQ would take into consideration similarities, vocabulary, information, block design, matrix reasoning, visual puzzles, digit span, arithmetic, symbol search, and coding as the core subtests (van Ool et al., 2017). Additionally, it includes the comprehension, picture completion, figure weights, letter-number sequencing, and cancellation as the supplemental subtests. Another score derived from the administration of the WAIS is general ability index (GAI) which takes into consideration the six subtests comprise the VCI and PRI indexes (Canivez, 2013). They include similarities, vocabulary, information, block design, matrix reasoning, and visual puzzles (Makizako et al., 2013). The subtests identify the individual’s skills in the use of working memory to solve practical problems in logical thinking, vocabulary, and arithmetic. 

The scoring in the latest version also incorporates computer software system known as the WAIS-IV Scoring Assistant. The administrator of the various test should just enter the raw scores and allow the software to perform various tasks. The Scoring Assistant generates concise score and statistical reports visually displayed in graphs and tables (Rosenberg, McDonald, Rosenberg, & Westbrook, 2016). The computer can convert the raw data into scaled scores effectively. The software is also an effective means of clearly identifying strengths and weakness discrepancies in the data collected. With PsychCorpCenter Platform as the foundation of the software, it can effectively provide the user with an integration of applications to produce cross battery analysis of scores (Alexander, & Liljequist, 2016). The scoring process is easier using the software available for purchasing. 

C. Interpretation of Results 

The interpretation of results is an integral measure of assessing the abilities and weaknesses of the individual’s intelligence. The 10 subtests are used to derive the distinct IQ scores of verbal comprehension, perceptual reasoning, working memory, processing speed, full-scale, and general ability (Kaplan & Saccuzzo, 2017). In this case, the scaled scores depict the sum of scores yielded in the numerous subtests while the composite scores are the IQ scores of the different intelligence levels (Benedict et al., 2012). The scaled scores range from 5 and below for Borderline IQ to 16 and above for Very Supperior (Rosenberg, McDonald, Rosenberg, & Westbrook, 2016). The average score is given as 10 with a deviation of 3. The percentile ranks provide a clear spectrum of the range of intelligence evident in the individual. The highest possible ranking is given as 99.9%, which reflects an IQ score of 130 and above (Benedict et al., 2012). An average percentile is 50% and reflects an IQ of 100 hence the score shows the performance of the test taker in comparison with other individuals their age. 

The 95% Confidence interval is a statistical measure used to demonstrate the lack of accuracy in the test. The statistical measure recognizes that during the administering of the test, 95% of the time the results will fall under the spectrum provided. Additionally, only on 5% of the time will the results fall outside of this spectrum. In this regard, the WAIS IQ and performance test has an accuracy of 95%, which is very good comparing to other similar tests (Makizako et al., 2013). The scores interpretation also takes into consideration the strengths and weaknesses where scores below 100 should receive significant attention. In this regard, the score shows that the participant is experiencing a weakness compared to other examinees of a similar age (Benedict et al., 2012). Struggles in working memory and processing speed may be a major hindrance in progression of an individual even when one experiences high scores in the other two indexes. 

D. Ease of use 

The most recent edition of the psychological test, WAIS-IV provides users with scoring and reporting software that significantly improves the ease of use. In this case, the administrator of the test will just have to enter the raw data into the system and allow the computer system to undertake the burdensome role of calculating the Scale, Composite, and Percentile scores that reflect the IQ and performance of the individual. The administrator of the test usually clinical psychologists or psychiatrist requires significant training to utilize it effectively (Makizako et al., 2013). A pre-recorded 20-30 minutes session enables the user to learn on the appropriate ways of utilizing the psychological test and receive accurate results. All that is required is a good internet connection and sound enabled computer system for listening in on instruction. The session provides clinicians with information on the manual and an overview of its use in evaluation of intelligence (Canivez, 2013). There are more recordings on similar information on scoring and ways of interpreting results. 

E. Cost of various forms of the test 

The test has various forms that customers may choose from depending on the need and use of the test. The first option is the pay per-report which is an attractive option for individuals who administer the WAIS-IV only a few times in a year or those who may want to pay only when the assessment is done (Makizako et al., 2013). As of 2008 the price per one complete test kit was set at $1,079 but a new kit now costs $1,235 from Pearson. The second option is an unlimited use subscription where one user gets unlimited scoring and reporting for one, three, or five years depending on the selected term of subscription. This may be a suitable option for individuals who administer the test several times a year. 

III. Psychometric Information 

The use of WAIS tests have been recognized as the most appropriate measure of evaluating the intelligence of an individual. The WAIS-IV is a substantially improved version of its predecessor. It involves the incorporation of four indexes structure with 15 subtests to measure intelligence (Weiss, Keith, Zhu, & Chen, 2013). Numerous scholars in neuropsychology and related fields have conducted research to identify the consistency of the test as used in normative and clinical samples (Nelson, Canivez, & Watkins, 2013). The results have demonstrates that in the use of competing higher order WAIS-IV four-and five-factor model in the assessment of intelligence, both structures are suitable for use in the identification of strengths and weaknesses (Weiss, Keith, Zhu, & Chen, 2013). However, it is evident that the five-factor model provided a better fit in identifying the validity and reliability of findings from the test. The higher order tests in four-factor models identifies the four indexes along with their 15 core and supplemental subtests. The five-factor model incorporates the use of the above mentioned and the five core subtests in verbal comprehension and perceptual reasoning indexes. 

In alternative research, it is evident that measures of processing speed are integral to ascertaining the validity of the diagnostic utility of the WAIS-IV. The study conducted by Erdodi and colleagues (2016) administers the subtests on a mixed clinical sample of 205 patients referred for neuropsychological assessment (Erdodi et al., 2016). The majority of the population was female at 53.3% and a means age of 45.1. The research sought to identify the effectiveness of the test through three composite measures of performance validity as criterion variables. PSI ≤79 provided a good estimation of the sensitivity and variable specificity. Coding scaled score ≤5 showed good specificity but low and variable sensitivity (Erdodi et al., 2016). Symbol search scaled score ≤6 demonstrates a good balance between sensitivity and specificity. Results suggest that processing speed based EVIs have the potential to provide a cost-effective and expedient method for evaluating the validity of cognitive data (Erdodi et al., 2016). Given their generally low and variable sensitivity, however, they should not be used in isolation to determine the credibility of a given response set (Erdodi et al., 2016). 

The As with previous intelligence test incremental validity studies, the WAIS–IV FSIQ accounted for statistically significant and generally large portions of WIAT–II and WIAT–III subtest and composite score variance. The WAIS-IV’s reliability and validity were examined through concurrent validity and reliability studies as well as confirmatory factor-analytic studies using first the core subtest contributing to FSIQ, followed by analyses including core and supplemental subtests (Alexander, & Liljequist, 2016). The improvement in the WAIS-IV’s (1) measurement of fluid reasoning, processing speed, and working memory, (2) improved reliability and validity especially at the extreme ranges of the instrument, and (3) extended floor and ceilings required extensive revision to the nine subtests retained from the WAIS-III in the WAIS-IV revision (Morrison, Simone, Ng, & Hardy, 2015). Non-age-normed overall scores were used as the predicted variable in the model in order to measure the effects of age as a continuous variable. Non-age-normed scores for each subtest were generated by the same scaling procedure on the entire Normative Sample (i.e., without age-binning the scores first) (Morrison, Simone, Ng, & Hardy, 2015). The non-age-normed subtest scores were then summed to generate an overall score. Age is a continuous numeric variable and gender was a factor with males as the reference group. 

IV. Summary, Impressions, and Critique 

The WAIS test is an effective measure of assessing the individual’s intelligence. The Wechsler Adult Intelligence Scale-IV (WAIS-IV) is an IQ test that is given by psychologists and measures global intellectual functioning. It includes both verbal and nonverbal components. The average score for all tests and subtests is 100; thus, a score of over 100 is above average and below 100 is below average. The standard deviation for IQ results is 15, which means that about 68% of scores fall between 85 and 115. The test results also provide the raw and scaled score for each test, as well as a percentile rank. The interpretation of results is an integral measure of assessing the abilities and weaknesses of the individual’s intelligence. 

References 

Alexander, L., & Liljequist, L. (2016). Determining the accuracy of self-report versus informant-report using the Conners’ Adult ADHD Rating Scale. Journal of Attention Disorders, 20 (4), 346-352. 

Benedict, R. H., Amato, M. P., Boringa, J., Brochet, B., Foley, F., Fredrikson, S., ... & Reder, A. T. (2012). Brief International Cognitive Assessment for MS (BICAMS): international standards for validation. BMC Neurology, 12 (1), 55. 

Canivez, G. L. (2013). Incremental criterion validity of WAIS–IV factor index scores: Relationships with WIAT–II and WIAT–III subtest and composite scores. Psychological Assessment, 25 (2), 484. 

Erdodi, L. A., Abeare, C. A., Lichtenstein, J. D., Tyson, B. T., Kucharski, B., Zuccato, B. G., & Roth, R. M. (2017). Wechsler Adult Intelligence Scale-(WAIS-IV) processing speed scores as measures of noncredible responding: The third generation of embedded performance validity indicators. Psychological Assessment, 29 (2), 148-157. 

Kaplan, R. M., & Saccuzzo, D. P. (2017). Psychological testing: Principles, applications, and issues . Ontario, Canada: Nelson Education. 

Makizako, H., Shimada, H., Park, H., Yoshida, D., Uemura, K., Tsutsumimoto, K., & Suzuki, T. (2013). Evaluation of multidimensional neurocognitive function using a tablet personal computer: Test–retest reliability and validity in community‐dwelling older adults. Geriatrics & Gerontology International, 13 (4), 860-866. 

Morrison, G. E., Simone, C. M., Ng, N. F., & Hardy, J. L. (2015). Reliability and validity of the NeuroCognitive Performance Test, a web-based neuropsychological assessment. Frontiers in Psychology , 6. 

Nelson, J. M., Canivez, G. L., & Watkins, M. W. (2013). Structural and incremental validity of the Wechsler Adult Intelligence Scale–Fourth Edition with a clinical sample. Psychological Assessment, 25 (2), 618-630. 

Rosenberg, H., McDonald, S., Rosenberg, J., & Westbrook, R. F. (2016). Measuring emotion perception following traumatic brain injury: the Complex Audio Visual Emotion Assessment Task (CAVEAT). Neuropsychological Rehabilitation , 1-19. 

van Ool, J. S., Hurks, P. P., Snoeijen-Schouwenaars, F. M., Tan, I. Y., Schelhaas, H. J., Klinkenberg, S., ... & Hendriksen, J. G. (2017). Accuracy of WISC-III and WAIS-IV short forms in patients with neurological disorders. Developmental Neurorehabilitation , 1-7.