Psychometric Properties of the Wechsler Abbreviated

Individual Differences Research 2011, Vol. 9, No. 4 , pp. 219-230 © 2011 Individual Differences Association, Inc.

www.idr-journal.com ISSN: 1541-745X

Psychometric Properties of the Wechsler Abbreviated Scale of Intelligence (WASI) with an Arab Sample of School Students Maher M. Abu-Hilal* Sultan Qaboos University

Mohammad A. Al-Baili & AbdelAziz Sartawi United Arab Emirates University

Faisal Abdel-Fattah King Saud University

Ibrahim A. Al-Qaryouti Sultan Qaboos University *Maher Abu-Hilal; P.O. Box 32; College of Education; Department of Psychology; Muscat, Oman P.C. 123; [email protected] (e-mail). ABSTRACT - The aim of this study was to determine the usability of the Wechsler Abbreviated Scale of Intelligence (WASI) by investigating its psychometric properties with an Arab sample of school students from the United Arab Emirates (UAE). Adaptations were made to some verbal items to fit the Emirates society. Some items of this scale were translated into Arabic language; other items were developed. The sample for this study consisted of 1721 individuals with an age range from 6-28 years from all geographic locations in the UAE, and was proportionally distributed between males and females. Data were analyzed with various procedures such as the analysis of variance and SEM. Stability and reliability estimates were computed for the subtests and the total IQ sca1es for each age group and for each gender, and all were adequate. The four scales discriminated well among the age groups and among normal individuals and individuals with special needs thus providing support to its usability for clinical assessment. The SEM analysis confirmed the structure of the scale with verbal and performance scales moderately correlated (.66).

The Wechsler tests of intelligence (e.g. WAIS, WISC) have become the preferred tests of clinical and school psychologists (Jensen, 1980). However, concerns about lengthy administration have led to the development of short forms (Donders & Axelrod, 2002; Lange & Iverson, 2007)). Meyer (2000) stated that "The demands of research protocols and managed care environments have imposed time constraints on psychological testing resulting in efforts to develop abbreviated forms of well-established psychometric measures." The Wechsler Abbreviated Scale of Intelligence (WASI) and the Wechsler Adult Intelligence Scale-Revised (WAIS-III) have been among those tests. Donders and Axelrod (2002) referred to the results of Ward (1990) indicating that WAISR produced psychometric indexes as accurate as those produced by full versions. Lange and Iverson (2007) acknowledged that "no short form was perfect for estimating index score," however, they reported that their results were "promising, with high predictive 219

Abu-Hilal... / Individual Differences Research, 2011, Vol. 9, No. 4, pp. 219-230

accuracy rates for all estimated WAIS-III index scores using two-subtest combinations" (p. 151). Also, Saklofske, Caravan and Scwartz (2000) concluded that WASI was found to be a good measure of intelligence. However, in their study, Donders and Axelrod (2002) found that the estimates of the WAIS-III were not as good as the full version of WAIS for clinical purposes. This paper reports the results of administering WASI to a representative sample from the UAE. The WASI was individually administered to individuals aged from 6 to 28 years. WASI yields the three traditional Verbal, Performance and Full Scale IQ scores. It consists of four subtests: Vocabulary (V), Block Design (BD), Similarities (S), and Matrix Reasoning (MR). Administration of all four subtests is a means of quickly estimating an individual’s verbal, non-verbal, and general cognitive functioning in approximately 30 minutes. Vocabulary and Matrix Reasoning are needed for estimating general cognitive functioning in 15 minutes. The English manual reported correlations of WASI subtests and scales with WISC-III and WAIS-III. All correlations were high and reflect concurrent validity of the WASI. For WISC-III, the correlations ranged from .69 (for Similarities) to .87 (for FSIQ-4). For WAIS-III, the correlations ranged from .66 (for Matrix Reasoning) to .92 (for FSIQ-4). Also, the manual reported good discriminant, factorial and construct validities. The main purpose of the WASI is to provide a good estimate of an individual’s general intellectual ability. The WASI subtests, therefore, were chosen not only on the basis of their high “g loadings” but also on the basis of the cognitive functioning tapped by each, such as verbal versus nonverbal abilities and fluid versus crystallized abilities. Psychologists, clinicians, and researchers in the Arab World badly need a fast and reliable measure of intelligence when screening for mental retardation or giftedness or for vocational or rehabilitation planning. They may need to retest or to obtain IQ estimates for individuals who are referred for psychiatric, psychological, and psycho-educational evaluations. Also, IQ estimates are needed for research purposes, such as preexperimental matching for cognitive ability. In all these cases a short form may be desirable due to time and other resources constraints. The purpose of this research was: (a) to develop and validate an Arabic version of the WASI; and to identify its psychometric properties for the UAE population. Organization of the WASI The four subtests of the WASI- Vocabulary, Block Design, Similarities and Matrix Reasoning- tap various facets of intelligence, such as verbal knowledge, visual information processing, spatial and non-verbal reasoning, and crystallized and fluid intelligence (Wechsler, 1999). These four subtests compose the Full Scale and yield the Full Scale IQ (FSIQ-4). The Vocabulary and Similarities subtests compose the Verbal Scale and yield the Verbal IQ (VIQ), and the Block Design and Matrix Reasoning subtests compose the Performance Scale and yield the Performance IQ (PIQ). The twosubtest form of the WASI, consisting of Vocabulary and Matrix Reasoning, provides only the FSIQ (FSIQ-2) (Ryan Carruthers, Miller, Souheaver, Gontkovsky and Zehr, 2003).

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Subtests Vocabulary The WASI Vocabulary subtest is a 42-item task. The first 4 items require the examinee to name pictures which are displayed one at a time. Items 5-42 are orally and visually presented words that the examinee orally defines. Vocabulary is a measure of the individual’s expressive vocabulary, verbal knowledge, and fund of information. Additionally, it is a good measure of crystallized intelligence and general intelligence. It taps other cognitive abilities such as memory, learning ability and concept and language development. Major changes have been made to this subtest in its Arabic version (Wechsler, 1999). Block Design The Block Design subtest consists of a set of 13 modeled or printed two-dimensional geometric patterns that the examinee replicates within a specified time limit using twocolor cubes. The subtest taps the abilities related to spatial visualization, visual-motor coordination, and abstract conceptualization. It is a measure of perceptual organization and general intelligence. In its Arabic version, no changes have been made to this subtest (Wechsler, 1999). Similarities This subtest contains 4 picture items and 22 verbal items. For each of items 1-4, the examinee is shown a picture of three common objects on the top row and four response options on the bottom row. The examinee responds by pointing to the one response option that is similar to the three target objects. For each verbal item, a pair of words is presented orally, and the examinee explains the similarity between the common objects or concepts that the two words represent. Similarities are a measure of verbal concept formation, abstract verbal reasoning ability, and general intellectual ability. The items in the Arabic version are different in content and order from the English version. Eight of the pairs of words were replaced by eight different pairs. The remaining pairs were only translated (Wechsler, 1999). Matrix Reasoning The Matrix Reasoning subtest is a series of 35 incomplete gridded patterns that the examinee completes by pointing to or stating the number of the correct response from five possible choices. Matrix Reasoning is a measure of nonverbal fluid reasoning and general intellectual ability. No changes have been made to this subtest in the Arabic version (Wechsler, 1999). Adaptations in the Arabic Version Based on the rationale provided by the developers of WASI (Wechsler, 1999) in the English version, the Arabic version reiterates the importance of the four subtests (vocabulary, block design, similarities and matrix reasoning) as major components of the general intellectual ability. In the Arabic version of WASI, the two verbal subtests have endured major changes, while the performance subtests have been kept intact with no changes made to their

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items. The team of the Arabic version of WASI followed the following steps in adapting the vocabulary and similarities subtests. 1. The words in the English version were reviewed and translated into Arabic and then were evaluated in terms of familiarity, difficulty and suitability to the local environment. 2. The team reviewed a number of verbal tests in Arabic such as an Egyptian and Kuwaiti versions of WISC and WAIS, Stanford Binet, Test of Verbal Intelligence (in Arabic), and tests of giftedness. 3. Few school teachers were selected and asked to propose words (vocabulary) and pairs of similar words (similarities) that may suit Emirati school children and should be variable in difficulty. 4. The team reviewed the proposed words and pairs and deleted the repeated words. About 69 words were retained as the team thought they were good for the targeted group. The words and pairs that are parallel to those in the English version of WASI were preferred. 5. The team administered the retained words and pairs of words to a pilot sample in schools and university to explore the kind of responses, clarity, and difficulty of words. 6. As a result of the analysis of responses in this screening stage, 38 words were retained based on their levels of difficulty and discrimination among age groups in the pilot study. 7. Likewise, 22 pairs of words were retained in the similarities subtest. 8. A group of 4 teachers specialized in Arabic were selected and given a key answer to give weights to answers and to give additional meanings, if necessary, to the words in case the list of meanings is not sufficient. 9. Correlation coefficients between achievement scores in Arabic and mathematics, and average performance in vocabulary and similarities subtests were computed. Method The WASI normative information presented in this report is based on a national normative sample highly representative of UAE national school children and university students. The WASI normative sample was stratified on sex, grade level and geographic region and included school children and university students (n=1721). School children up to high school were 1609 students. University students were 112 (boys = 33 and girls =79) from the United Arab Emirates University (UAEU), but only 85 completed the tests (75 girls and 10 boys). Table 1 provides a description of the sample by age group in years. The sample of university students was selected according to college, level and gender. Statistical analyses are based on the sample of school children only (n=1609). To test construct validity and discriminant validity, mentally retarded (n=50), physically disabled (n=10) and deaf (n=49) samples were used. These three samples came from an institution (Sharjah City for Humanitarian Services). The classification of those individuals was based on the institution's criteria. A group of 30 psychologists in the Ministry of Education and Youth was selected and trained to administer WASI-A.

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About 15 protocols were mishandled and were dropped from the standardization sample. The Vocabulary and Similarities subtests were not administered to deaf individuals. For those with handicapped or special needs, a specialist administered the tests and no norms have been produced for mentally retarded and deaf children. Table 1 Normative Sample by Age Group in year Age group 6 7 8 9 10 11 12 13 14 15 16 17 >17 Total

n 121 111 133 112 153 113 150 135 151 132 153 90 83 1637

Percent 7.4 6.8 8.1 6.8 9.3 6.9 9.2 8.2 9.2 8.1 9.3 5.5 5.1 100.0

Data Analysis For each age group, the total raw scores of each subtest were first converted to percentiles. Next, the raw scores were converted into normal scores. The normal scores were then converted into T-score scale with a mean of 50 and a standard deviation of 10. To eliminate irregularities, means, skewness and variance values across the age groups were examined and minor fluctuations were smoothed. The T-score equivalents of subtest raw scores are available with the authors. The sums of subtest T-scores for the WASI IQ scales were calculated by summing each individual’s actual age T-scores on the relevant subtests. For the four-subtest form, the Verbal score is the sum of the T-scores on Vocabulary and Similarities, the Performance score is the sum of the T-scores on Block Design an Matrix Reasoning, and the Full Scale score is the sum of the T-scores on all four subtests. For the two-subtest form of the WASI, the Full Scale score is the sum of T-scores on Vocabulary and Matrix Reasoning. Results The statistical properties of the Arabic version of WASI include stability, reliability coefficients, and validity estimates. This section reports and discusses these statistics as they relate to the quantitative interpretation of scores on the Arabic version of the WASI. Reliability A reliable test will have relatively small measurement error and consistent measurement results within one administration and on different occasions, if the underlying construct has not changed (Guilford & Fruchter, 1978). The reliability of a

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test should always be considered in the interpretation of obtained test scores and differences between an individual’s test scores on multiple occasions. Test-Retest Reliability. The Arabic version of WASI was administered twice to a sample of (N=60) individuals with a gap between test and retest ranged between 1 to 9 weeks. Table 2 shows the stability estimates for the four subtests. All correlation coefficients (ranged from .83 to .91) between test and retest are significant at p < .0001. Also, stability coefficients were computed for the verbal and performance scales. They were .97 and .90, respectively. Table 2 Test-Retest Reliability and High and Low Alphas of WASI Subtests and IQ Scales Subtest Vocabulary Similarities Block Design Matrix Reasoning Verbal Performance FSIQ-4 FSIQ-2

Test-retest Reliability (n=60) .88 .91 .83 .86 .97 .90 .-.--

HI α .96 .93 .88 .94 .94 .89 .94 .93

LOW α .80 Age 9 .75 Age 6 .67 Age 8 .87 Age 6 .76 Age 6 .73 Age 6 .81 Age 6 .81 Age 6

Internal Consistency of Subtests. Cronbach alphas for internal consistency were computed for each age group. Table 2 illustrates the high and low alphas for each subtest. The lowest alphas were found for age 6, 8 and 9. Alpha for Block Design was lower than any of the other three subtests (high = .88). The reliability estimates in this study compare rather well with those produced by the authors of the WASI English version. Also, Table 3 shows the standard error of measurement for WASI subtests by age group. Table 3 Standard Errors of Measurement of the WASI Subtests and IQ Scales by Age Group Subtest/Scale Vocabulary Similarities BD MR FSIQ-4 FSIQ-2

6 .21 .12 .10 .15 .75 .52

7 .27 .18 .17 .22 1.30 .79

8 .22 .18 .20 .41 1.53 .88

9 .31 .21 .40 .35 1.79 .90

10 .41 .23 .34 .34 2.04 1.32

11 .60 .35 .57 .41 2.48 1.53

12 .34 .30 .65 .23 2.28 1.27

13 .59 .32 .60 .23 2.84 1.79

14 .50 .28 .44 .23 2.32 1.47

15 .65 .37 .42 .30 2.65 1.65

16 .45 .28 .53 .24 2.43 1.40

17 .68 .50 .55 .23 3.11 2.04

> 17 .73 .37 .62 .38 2.88 1.64

Validity Content Validity. The test manual in its original language provides an explanation of the content validity of WASI. Content validity is made up of two components: content coverage and content relevance. Content validity is not necessarily based on statistics or empirical testing; rather, it is the degree to which the test items adequately represent and relate to the trait or function that is being measured. Content coverage means that the items or subtests sample the full range of the abilities that the test is intended to measure. Similarly, content relevance means that the items or subtests relate to the abilities the test

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is designed to measure. These two properties, however, do not ensure “true” validity. Rather, they help prevent construct validity from being jeopardized by construct underrepresentation or construct irrelevance. Construct Validity. Construct validity refers to the degree to which test scores reflect an abstract psychological trait or construct. The construct validation process involves both logical and empirical components. In the logical component of construct validation, the content of the test items should be relevant to the construct being measured. Whilst the empirical component of construct validation may include one or more of the following procedures: (1) correlation between test scores and designated criterion variables; (2) factor analysis; and (3) differentiation between groups. Correlations of the WASI Subtest, IQ Scales, Verbal and Math Achievements The evidence of the convergent validity and discriminant validity of the WASI are based on the inter-correlations of the WASI subtests. For this purpose, two predictions were made. First, it was predicted that each of the four subtests would have moderate to high correlations with each other. Furthermore, because the subtests are all related to the g factor, the correlations among them were expected to be from moderate to high. Second, it was predicted that Vocabulary and Similarities would have higher correlations with each other than with Block Design and Matrix Reasoning. Similarly, Block Design and Matrix Reasoning would have higher correlations with each other than with the subtests composing the verbal scale. Table 4 Inter-correlations, Means, and Standard Deviations of T Scores and Sum of T Scores of Subtests, IQ Scales and Achievement in Math and Arabic Subtests/Scales V Vocabulary (V) 1 Similarities (S) .69** Block Design (BD) .44** Matrix Reasoning (MR) .35** Verbal (VE) .92** Performance (P) .46** Full Scale-4 (FS-4) .80** Full Scale-2 (FS-2) .82** + Arabic Score (AS) .60** + Math Score (MS) .61** M 50 SD 9.96 Note. **p < 0.01 level (2-tailed)

S

Subtests and Scales BD MR VE

P

F S-4

F S-2

1 .46** 1 .38** .44** 1 .92** .49** .40** 1 .49** .85** .85** .52** 1 .82** .76** .70** .88** .86** 1 ** ** ** ** .65 .54 .82 .80 .80** .92** 1 ** * ** .49 .44 .53 .59** .51** .70** .69** .41* .32 .31 .56** .36* .62** .64** 50 50 50 100 100 200 100 9.96 9.96 9.96 18.30 16.92 30.71 16.35 *p < 0.05 level (2-tailed), + Self-report marks. n = 53.

AS

MS

1 .67** 130 56

1 131 75

Factor Analysis Confirmatory factor analysis (CFA) was conducted for a model of two latent factors: verbal (measured by vocabulary and similarities) and performance (measured by matrix reasoning and block design) that are assumed to be correlated. Vocabulary was left free to load on the performance latent factor. The maximum likelihood method was used to analyze the data. The analysis produced excellent fit of data to model. Because the χ2

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statistic is widely known to be sensitive to sample size (Hu & Bentler, 1991), we also evaluated model fit using the comparative fit index (CFI), the Tucker-Lewis index (TLI) and the root mean square error of approximation (RMSEA). According to Hu and Bentler (1991), a good model fit is indicated by CFI and TLI values close to or above .95, and when the RMSEA value is ideally below .10. Examination of the hypothesized model showed an excellent fit: 2 = 5.53 (2), p > .05; CFI = .998; TLI = .994; RMSEA = .033 Given no logical revisions were warranted, the next step was to run an unconstrained model simultaneously for the male and female groups. This step serves as a baseline for testing the equality of parameter constraints in subsequently increasingly restrictive nested models. After establishing a good-fitting baseline model (2 = 6.446 (4), p > .05; CFI = .999; TLI = .996; RMSEA = .019), a model constraining the equality of factor loadings across gender was tested and produced a good fit (2 = 6.532 (5), p > .05; CFI = .999; TLI = .998; RMSEA = .014). The covariances of the latent factors were the next set of constraints imposed and the results revealed a good model fit, 2 = 12.158 (8), p > .05, CFI = .998; TLI = .996; RMSEA = .018. Finally, the constraints of equality were imposed on the measurement residuals across gender but the results did not reveal as good fit as the previous models (2 = 63.346 (12), CFI = .970, TLI = .970, RMSEA = .051). Ryan et al. (2003) employed exploratory factor analysis on the responses of the American normative sample and a heterogeneous clinical sample to reproduce a twofactor model for WASI. They reproduced a clear two-factor model which was congruent across the two types of samples. Discrimination Among Normal and Individuals with Special Needs The assessment of the clinical sensitivity and utility of the WASI was based on data collected from various populations including individuals with mental retardation and hearing impairment. MANOVA was conducted to compare performances of normal children with mentally retarded and physically disabled children. Table 5 presents the results. Table 5 Means, Standard Deviations of Raw Scores, and F Ratio for Vocabulary, Similarities, Block Design and Matrix Reasoning by Student Type Subtest

Student Type Normal MR Ph. Disability (n=598) (n=50) (n=10) M 35.82a 15.98b 35.00a Vocabulary SD 16.62 9.00 14.64 M 20.07a 8.18b 18.90a Similarities SD 10.66 6.43 5.78 M 22.79a 9.04b 15.20 Block Design SD 14.81 5.44 13.38 M 21.27a 12.56b 20.80a Matrix Reasoning SD 9.43 5.71 7.21 Note. Different letters in one row denote significant difference,

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Deaf (n=49)

F 98.49* 77.65*

25.16a 12.41 24.33a 5.49 p < .05

17.00* 17.14* *p < .001.


For vocabulary, the normal individuals scored significantly higher than mentally retarded individuals. Also, physically disabled individuals scored significantly higher than mentally retarded. No significant difference existed between normal and physically disabled individuals. For similarities, a similar pattern of differences occurred. For the performance scales, matrix reasoning and block design, deaf individuals outperformed the other three groups. For matrix reasoning, the significant difference occurred between mentally retarded and other three groups; but no significant difference occurred among normal, deaf and physically disabled individuals. However, the most clinically revealing is the block design subtest. Normal and deaf scored significantly higher than mentally retarded and physically disabled individuals. Though not significantly, the deaf individuals outperformed normal individuals. Physically disabled and mentally retarded individuals performed poorly on this subtest. This subtest requires both coordination and use of hand to perform skills that may be weak among mentally retarded and physically disabled individuals. In sum, it is clear from the results that normal individuals scored significantly higher than mentally retarded physically disabled individuals on all scales. Deaf individuals outperformed their normal, mentally retarded and physically disabled counterparts on both performance scales: block design and matrix reasoning. Discrimination Among Age Groups Table 6 presents means, standard deviations and F ratios for differences among raw scores of the WASI subtests for different age groups. The means for subtest scores indicate that a significant increase exists as we move from younger to older ages. The post hoc results reveal that as children are at the age of 13 and older the differentiation among age groups becomes weaker and less significant. Also, ages 6, 7, 8 and 9 seem to make a homogenous group although non-significant differences exist in favor of older ages. Ages 10 and 11 tend to make a homogenous group; and ages 12, 13 and 14 make one homogenous group with the same trend of differences as in the other previous homogenous groups. Differences on some subtests become even weaker among the ages 15, 16 and 17. Discussion In this study we set out to examine the usability of the WASI in a milieu different from the one in which the instrument was originated. The various analyses yield strong support for the use of the WASI as a brief measure of intelligence with Arab school children. Specifically, all of the indicators in this study suggest that intelligence as a construct is not culture specific despite the criticism that has been directed to the Western framework of intelligence. It should be pointed out that two of the scales are culture free, i.e. block design and matrix reasoning; while vocabulary and similarities are culture bound. The latter two scales have endured significant changes to suit the culture of the subjects participated in this study. The results of the study indicate that the tow culturebound scales produced better reliability and validity indices than the culture-free scales. The results of this study demonstrate that the verbal scales have better reliabilities than the performance scales. The least reliable scale has been the block design scale. This scale, although most culture-free, has been found to be the most culture bound. The Block design scale is a speed subtest and involves time. Several cross-cultural researchers

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have found that time is perceived and observed differently in different cultures (Maehr, 1974). In the Arab culture, time is not strictly observed and adhered to by Arab Table 6 ANOVA Results of Age Differences in Raw Scores for the Four Subtests Subtest Vocabulary Total Similarities Total Block Design Total Matrix Reasoning Total Note. *p < .001

Age 6 7 8 9 10 11 12 13 14 15 16 17 >17 6 7 8 9 10 11 12 13 14 15 16 17 >17 6 7 8 9 10 11 12 13 14 15 16 17 >17 6 7 8 9 10 11 12 13 14 15 16 17 >17

M 12.53 15.45 18.85 19.00 27.28 25.90 33.16 36.86 38.48 40.32 46.43 43.63 45.72 31.76 6.35 8.89 9.91 9.96 14.90 13.64 19.96 20.73 22.96 21.65 27.00 24.76 26.79 17.95 5.48 7.76 8.77 10.81 16.10 16.58 22.10 24.39 24.85 28.83 29.43 29.63 32.94 20.31 6.41 9.61 12.19 15.05 18.38 17.67 21.92 22.50 22.78 23.68 23.35 24.16 24.40 19.09

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SD 5.68 7.54 8.57 5.44 11.45 12.30 10.56 14.79 14.09 15.77 13.65 19.19 19.56 16.92 3.10 5.37 4.60 4.70 7.63 7.22 7.43 8.74 8.10 8.99 7.71 11.29 11.65 10.22 3.94 7.72 4.88 6.75 9.24 10.26 12.07 13.52 11.16 13.31 13.04 14.42 14.05 13.95 4.21 6.54 7.43 6.60 7.23 7.37 6.61 6.62 5.60 5.84 6.67 6.67 6.37 8.51

F 94.73* 96.89* 82.80* 96.33*


individuals (Barakat, 1993; Sharabi, 1975). Children are not socialized and trained to manage and deal with time the same way individuals in industrialized western countries are. Hence, this may have had an effect on the sample's observation of time when they performed the test. Some differences in reliability estimates occurred between the results reported here and those reported in the WASI Manual, particularly in the block design subtest. The pattern of correlations between subtests and IQ scores reported here are relatively similar to that in WASI Manual. Consistently with the results of Ryan et al. (2003), the factor analysis of our data supports the two-factor model reported in the WASI Manual and provides support for the construct validity of the test. Thus the WASI factor structure appears to generalize to male and female samples. Limitations and Areas for Future Research As WASI is being administered for the first time in the Arab World, the results of this research must be considered with some caution. Much work needs to be done to further validate its use with more heterogeneous samples. For example, congruence or invariance among normal individuals, individuals with special needs, and clinical samples was not tested in our research. Therefore, future research outside the Western hemisphere, particularly, in the Arab World, should consider samples with adequate size from clinical populations. This is particularly true since previous research (Axelrod, 2002) found that WASI -as a short form- was not as accurate as the full WAIS-III. Axelrod based his conclusion on the administration of WASI and WAIS-III to a small sample (N=72) of patients. The WASI structure was based on the total sample and not on the different age groups of the standardization sample. Further research may consider WASI structure across age groups and test if the structure is invariant. Also, WASI structure can be tested across clinical populations and test its invariant structure. The standardization sample included individuals with age less than 25 years and the results reported here are based on individuals who were around the age of 17. Researchers in the Arab World may direct their efforts toward samples of adults and elder people to validate the WASI. Then recommendations can be made regarding the use of WASI with such samples. WASI manual provided norms for age groups older than 25 years up to 89 years and this can be done in the Arab World. Notwithstanding the above limitations, the WASI appears to offer a fast and cost efficient assessment of intelligence in the Arab culture. It can be used as a screening tool with various age groups younger than 25 years as well as various ability groups. Furthermore, due to high correlations among the subtests and IQ scales further reduction of time and effort can be made by using only part of the instrument, full scale-2. Author Note This paper is based on a research that was supported by the United Arab Emirates References Barakat, H. (1993). The Arab world: Society, culture and state. Berkeley: University of California Press.

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