Education-stratified base-rate information on discrepancy scores within and between the Wechsler Adult Intelligence Scale--Third Edition and the Wechsler Memory Scale--Third Edition

The Wechsler Adult Intelligence Scale--Third Edition (WAIS-III; D. Wechsler, 1997a) and the Wechsler Memory Scale--Third Edition (WMS-III; D. Wechsler, 1997b) are 2 of the most frequently used measures in psychology and neuropsychology. To facilitate the diagnostic use of these measures in the clinical decision-making process, this article provides information on education-stratified, directional prevalence rates (i.e., base rates) of discrepancy scores between the major index scores for the WAIS-III, the WMS-III, and between the WAIS-III and WMS-III. To illustrate how such base-rate data can be clinically used, this article reviews the relative risk (i.e., odds ratio) of empirically defined "rare" cognitive deficits in 2 of the clinical samples presented in the WAIS-III--WMS-III Technical Manual (The Psychological Corporation, 1997).     

Values for comparison of WAIS-III index scores with overall means

The Wechsler Adult Intelligence Scale--Third Edition (WAIS-III; Wechsler, 1997b) provides factor-based index scores but allows only for pairwise comparison of these scores, producing inflated Type I error rates and reducing profile interpretability. This article provides tables for simultaneous comparison to the overall mean index score, thus reducing error rates and aiding interpretation. The Working Memory Index or Processing Speed Index can also be specifically compared when an individual is believed to have a condition, such as a learning disability or traumatic brain injury, associated with the selective depression of these indexes. Tables for the infrequency of specific differences are also provided, allowing the practitioner to note how unusual an obtained difference is in the general population.     

Graduate student WAIS-III scoring accuracy is a function of full scale IQ and complexity of examiner tasks

Research on the Wechsler Adult Intelligence Scale-Revised and Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) suggests that practicing clinical psychologists and graduate students make item-level scoring errors that affect IQ, index, and subtest scores. Studies have been limited in that Full-Scale IQ (FSIQ) and examiner administration, recording, and scoring tasks have not been systematically varied. In this study, graduate student participants score a high (FSIQ = 112) and low (FSIQ = 85) IQ record form in one of two stimulus conditions: digitized film clips (N = 13) or partially completed record forms (N = 11). Results demonstrate that examiners are less accurate in the high IQ condition, and that recording examinee responses from scoring video clips results in more scoring errors. Obtained FSIQs are significantly higher than criterion IQ scores in the high IQ condition (8.46 for video condition, 2.55 for record form condition). Self-reported proficiency in WAIS-III administration and scoring is positively related to number of scoring errors.     

Performance of children with epilepsy and normal age-matched controls on the WISC-III.

Research findings regarding the effects of childhood epilepsy on general intelligence have produced variable results. The aim of this study was to investigate the effects of epilepsy, age of seizure onset, and Antiepileptic Drugs (AED) on intellectual ability as assessed by the Wechsler Intelligence Scale for Children, 3rd Edition (WISC-III; Wechsler, 1991). This study included children with epilepsy assessed with the WISC-III who achieved either a Full Scale, Verbal Scale, or Performance Scale IQ score >or= 70. A clinical sample of children diagnosed with epilepsy (n = 32) were age- and gender-matched with subjects from the normative standardization sample for the WISC-III, yielding a total sample of 64 subjects. Comparison using a MANOVA revealed significant differences across WISC-III Index standard scores (p = 0.0005) and subtest scaled scores (p = 0.0013), with control participants performing better than epileptic participants. Secondary analyses were also conducted considering monotherapy (n = 14) versus polytherapy (n = 11), and age of seizure onset (<6 years, n = 12; 6 > years, n = 15). MANOVA comparisons revealed no significant differences between groups across WISC-III Index standard scores.     

Some supplementary methods for the analysis of WAIS-IV index scores in neuropsychological assessment

Objectives. To develop supplementary methods for the analysis of the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) in neuropsychological assessment. Design and Methods. Psychometric. Results. The following methods are made available: (a) provision of traditional confidence intervals (CIs) on index scores, (b) expression of the endpoints of CIs as percentile ranks; (c) quantification of the number of abnormally low index scores exhibited by a case and accompanying estimate of the percentage of the normative population expected to exhibit at least this number of low scores; (d) quantification of the reliability and abnormality of index score deviations from an individual's index score mean (thereby offering an alternative to the pairwise approach to index score comparisons available in the WAIS-IV manual); (e) provision of CIs on an individual's deviation scores or pairwise difference scores, (f) estimation of the percentage of the normative population expected to exhibit at least as many abnormal deviations or abnormal pairwise differences as a case; and (g) calculation of a case's Mahalanobis distance index (MDI), thereby providing a multivariate estimate of the overall abnormality of an index score profile. With the exception of the MDI, all the methods can be applied using tables provided in this paper. However, for ease and speed of application, and to reduce the possibility of clerical error, all the methods have also been implemented in a computer program. Conclusions. The methods are useful for neuropsychological interpretation of the WAIS-IV.     

WAIS-III percentile scores by education and sex for U.S. and Canadian populations

Tables are presented for the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) IQ and index scores by education level for both the U.S. and Canadian normative samples. This allows clinicians to provide more accurate identification of relative strengths or weaknesses, compared to expectations from an individual's background, rather than the general population. Because sex differences are notable on the Processing Speed Index, data for this measure are presented separately. The similarities and differences between the two national samples are noted, with particular reference to the relatively weaker demographic effects found in the Canadian sample.     

Analysis of WAIS-IV index score scatter using significant deviation from the mean index score

The Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) does not include verbal IQ and performance IQ scores, as provided in previous editions of the scale; rather, this edition provides comparisons among four index scores, allowing analysis of an individual's WAIS-IV performance in more discrete domains of cognitive ability. To supplement the pairwise index score comparisons included in the WAIS-IV manuals, this article describes the use of the mean of the four index scores (the average index score) as a baseline for analyzing index score variability and as a method for identifying strengths and weaknesses within an individual's index score pattern. Davis's formula was used to calculate critical values for the identification of index scores with a statistically significant difference from the average index score. Subsequent analysis of the WAIS-IV normative sample indicates that variability in performance at the index score level is not uncommon in the general population. More than 70% of individuals in the normative sample have at least one index score that differs significantly from their mean index score. This variability in index score performance appears to have little relationship to age or gender, but it is strongly related to the full-scale IQ.     

A confirmatory analysis of the factor structure and cross-age invariance of the Wechsler Adult Intelligence Scale-Third Edition

In the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III; D. Wechsler, 1997), the manual reports several confirmatory factor analyses in support of the instrument's latent factor structure. In practice, examiners frequently compare an examinee's score from a current administration of the WAIS-III with the results from a previous test administration. Implicit in test-retest score comparisons is evidence that scores retain similar interpretive meaning across time. Establishing an instrument's factorial invariance provides the foundation for this practice. This study investigated the factorial invariance of the WAIS-III across the instrument's 13 age groups. The overall results from this study generally support both configural and factorial invariance of the WAIS-III when the 11 primary tests are administered.     

Validity of the Wechsler abbreviated scale of intelligence and other very short forms of estimating intellectual functioning

Performance on the Wechsler Adult Intelligence Scale-III (WAIS-III) was compared to performance on the Wechsler Abbreviated Scale of Intelligence (WASI), as well as short form estimations of intellectual functioning derived from WAIS-III performance, in a mixed clinical sample of 72 participants. The WASI verbal IQ (VIQ) score was significantly higher than the WAIS-III VIQ, whereas performance IQ (PIQ) estimates all differed from actual WAIS-III PIQ and full scale IQ (FSIQ). Correlations of WAIS-III scores with WASI scores were consistently lower than were correlations between the WASI-III and all other short forms. Although maintaining administration times of 15 minutesfor a two-subtest FSIQ and 30 minutes for a four-subtest FSIQ, the WASI did not consistently demonstrate desirable accuracy in predicting scores obtained from the WAIS-III. The results suggest that clinicians should use the WASI cautiously if at all, especially when accurate estimates of individuals' WAIS-III results are needed.     

How does the strength of the relationships between cognitive abilities evolve over the life span for low-IQ vs high-IQ adults?

The present study was designed to examine how the correlations between cognitive abilities evolve during adulthood. Data from 1104 participants on the French version of the Wechsler Adult Intelligence Scale-Third Edition were analyzed. The entire sample was divided into four age groups (16–24 years; 25–44 years; 45–69 years and 70–89 years), which were themselves split into two IQ-levels using the mean standard score on Vocabulary and Block Design. For every age group, the mean correlation between subtest scores of low-IQ participants was higher than that of high-IQ participants. There was also no interaction between age and IQ for the strength of subtest relationships. Indeed, the effect sizes of correlation differences between low- and high-IQ participants appeared to be relatively constant across age. A general developmental schema of how the strength of correlations between cognitive abilities of low- and high-IQ individuals evolves during the entire life span is sketched in the discussion.     

Structure of the Wechsler Intelligence Scale for Children--Fourth Edition among a national sample of referred students

The structure of the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV; D. Wechsler, 2003a) was analyzed via confirmatory factor analysis among a national sample of 355 students referred for psychoeducational evaluation by 93 school psychologists from 35 states. The structure of the WISC-IV core battery was best represented by four first-order factors as per D. Wechsler (2003b), plus a general intelligence factor in a direct hierarchical model. The general factor was the predominate source of variation among WISC-IV subtests, accounting for 48% of the total variance and 75% of the common variance. The largest 1st-order factor, Processing Speed, only accounted for 6.1% total and 9.5% common variance. Given these explanatory contributions, recommendations favoring interpretation of the 1st-order factor scores over the general intelligence score appear to be misguided.     

Concurrent validity of the Wechsler abbreviated scale of intelligence and the Kaufman brief intelligence test among psychiatric inpatients

This study examined the convergent and discriminant validity of the Wechsler Abbreviated Scale of Intelligence and the Kaufman Brief Intelligence Test for 85 psychiatric inpatients. The correlation between the WASI Full Scale and K-BIT Composite IQ scores was significant (r = .89, p < .001). Multitrait-multimethod analysis of the subtest scores showed that the K-BIT had higher internal consistency for its two subtests but, therefore, less differentiation of cognitive functioning than the brief Wechsler scale, as would be expected due to the larger number and diversity of the latter subtests. Correlations among the Wechsler scale subtests were lower than among those for the K-BIT, so the former may tap different cognitive functions and yield more clinically useful information than the latter. This brief Wechsler scale appears to be a valid screening measure of verbal, performance. and general intellectual ability for use with an inpatient psychiatric population when considerations of the setting or patient preclude administration of a longer measure of intellectual ability.     

Criterion-related bias with the guide to the assessment of test-session behavior for the WISC-III and WIAT: Possible race/ethnicity, gender, and SES effects

Using the Guide to the Assessment of Test-Session Behavior for the WISC-III and WIAT (GATSB), Anglo examiners recorded test observations for 969 children between the ages of 6 and 16 years. The children came from the standardization and validity-study samples of GATSB ratings completed with the Wechsler Intelligence Scale-Third Edition (WISC-III) (Wechsler, 1991). The sample differed by race (Anglo, black, Latino), socioeconomic status (SES) (high, middle, low), and gender. GATSB ratings and WISC-III Verbal, Performance, and Full Scale IQs were compared. Correlations between the GATSB and WISC-III were generally moderate (average R = -.27). Children who exhibited higher levels of avoidance, inattentiveness, and uncooperative behaviors while being tested tended to exhibit lower WISC-III scores. This pattern held true for Anglos, blacks, and Latinos; for girls and boys; and for those from high-, middle-, and low-SES homes. Evidence was generally absent that Anglo examiners display bias in black-Anglo, gender, or SES comparisons. However, consistent differences were noted between Latino and Anglo children. Examiners tended to rate Latinos as displaying better test behaviors than Anglos when children's IQs were below average, but comparable when IQs were average and above. Thus, the GATSB generally displayed similar intrasession validities for children who differ by race/ethnicity, gender, and SES.     

Expanding the ecological validity of WAIS-IV and WMS-IV with the Texas functional living scale

Assessment of functional status is an important aspect of clinical evaluation. As part of the standardization of the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) and Wechsler Memory Scale-Fourth Edition (WMS-IV), participants completed the Texas Functional Living Scale (TFLS), a measure of Instrumental Activities of Daily Living. The relationships between TFLS and WAIS-IV and WMS-IV were examined in both normally developing and clinical samples. In general, the highest correlations were between TFLS and measures of general cognitive ability (WAIS-IV FSIQ [Full Scale IQ] and GAI [General Ability Index]) and working memory (WAIS-IV WMI [Working Memory Index] and WMS-IV VWMI [Visual Working Memory Index]). Across the clinical populations, working memory subtests were generally strongly related to TFLS performance, although this relationship was more consistent with WAIS-IV than WMS-IV. Contrast scaled scores are presented for the TFLS based on WAIS-IV or WMS-IV performance. These scores allow the evaluation of functional abilities within the context of cognitive and memory ability, enhancing and expanding the utility of the WAIS-IV and WMS-IV.     

Neuropsychological status of French children with developmental dyslexia and/or developmental coordination disorder: Are both necessarily worse than one?

Developmental dyslexia (DD) and developmental coordination disorder (DCD) co-occur frequently, raising the underlying question of shared etiological bases. We investigated the cognitive profile of children with DD, children with DCD, and children with the dual association (DD + DCD) to determine the inherent characteristics of each disorder and explore the possible additional impact of co-morbidity on intellectual, attentional, and psychosocial functioning. The participants were 8- to 12-year-olds (20 DD, 22 DCD, and 23 DD + DCD). Cognitive abilities were assessed by the Wechsler Intelligence Scale for Children – Fourth Edition (WISC-IV) and the Continuous Performance Test – Second Edition (CPT-II) and behavioral impairments were evaluated by the Child Behavior Checklist (CBCL). No differences were found between the three groups on attention testing (CPT-II) or psychosocial characteristics (CBCL), but a higher percentage of DD + DCD children had pathological scores on psychosocial scales. Significant between-group differences were observed on Processing Speed Index scores and the block design and symbol search subtests, where DD children fared better than DCD children. No significant differences were evident between the co-morbid vs. the pure groups. Our results clearly show significant differences between children with DD only and children with DCD only. In particular, visuo-spatial disabilities and heterogeneity of intellectual profile seem to be good markers of DCD. However, it should be noted that despite these distinct and separate characteristics, a common cognitive profile (weaknesses and strengths) is likely shared by both neurodevelopmental disorders. Surprisingly, concerning co-morbidity, DD + DCD association is not associated with a decrease in intellectual or attentional capacities.     

Comparative relationships of the Wechsler Adult Intelligence Scale—Revised (WAIS-R) and the Wechsler Adult Intelligence Scale (WAIS) to the Wechsler Memory Scale (WMS)

This study investigated whether the Wechsler Adult Intelligence Scale — Revised (WAIS-R) and Wechsler Adult Intelligence Scale (WAIS) demonstrate similar patterns of relationship with the Wechsler Memory Scale (WMS). Sixty VA patients were administered the WAIS-R and WMS and 60 completed the WAIS and WMS. The groups were comparable in terms of demographic variables. Pearson correlations were computed between the subtest and IQ scores from the intelligence scales and the scores from the WMS for each group. Comparison of the resulting correlations for the WAIS-R group with those of the WAIS subjects demonstrated only four significant differences, indicating that the WAIS-R and WAIS variables covary in a similar manner with the WMS scores. Following factor analysis of the test data for both groups, coefficients of congruence indicated a high degree of similarity between the two factor solutions. Essentially the same relationships emerged between intelligence variables and the WMS regardless of which scale was administered.     

The First Twenty Years of the Will and the Ways: An Examination of Score Reliability Distribution on Snyder’s Dispositional Hope Scale

C. R. Snyder has established hope theory as an important contributor to positive psychology. As the empirical evidence continues to grow, hope researchers need to have confidence that their measures will produce reliable scores. This study presents a reliability generalization on both the internal consistency and test–retest reliability estimates from Snyder’s dispositional hope scale. While over 300 published works were found to have cited the target article 74 present internal consistency scores and 17 reported scores for test–retest reliability. The results of the reliability generalization suggest support for the score reliabilities produced by the dispositional hope scale. However, internal consistency was higher for studies using the eight-item response format (α = 0.82) compared to those using the four-item response format (α = 0.77). Additionally, the test–retest score reliability was high 0.80 with no statistically significant differences by response format. Findings also demonstrated that score reliability estimates were not significantly influenced by the coded sample characteristics.     

WISC-R subtest but no overall VIQ-PIQ difference in Dutch children with PDD-NOS

VIQ-PIQ differences have been studied in children with autism and Asperger syndrome but have not been studied in a separate group of children with PDD-NO, although, PDD-NOS has a much higher prevalence rate than autism and deficits in communication and social interaction are severe. The Wechsler Intelligence Scale for Children-Revised (WISC-R) was administered to 100 children, aged 6-12 years, with PDD-NOS (n = 76), autism (n = 13), and Asperger syndrome (n = 11). PDD-NOS was diagnosed using explicit research criteria. No overall differences between VIQ and PIQ were found in PDD-NOS and autism. Peaks in the subtest scores on Information, Similarities, Picture Arrangement, and Mazes, and troughs in the subtest scores on Comprehension, Digit Span, and Coding were demonstrated in children with PDD-NOS. Their score on the Freedom from Distractibility factor was lower than the scores on the Verbal Comprehension factor and the Perceptual Organization factor. Children with PDD-NOS seemed to have a similar VIQ-PIQ profile as children with autism, and on the subtest level children with PDD-NOS showed some similarities to children with Asperger syndrome or autism. It was not possible to distinguish PDD-NOS from autism or Asperger syndrome by using IQ scores.     

Evaluation of the validity of the Wechsler Intelligence Scale for Children--Third Edition comprehension and picture arrangement subtests as measures of social intelligence

Clinical lore suggests that the Wechsler Intelligence Scale for Children--Third Edition (D. M. Wechsler, 1991) Comprehension and Picture Arrangement scores may be used as indices of social intelligence. This study evaluated this supposition by comparing these subtest scores with mother- and teacher-reported social functioning in 142 children with ADHD and 30 control children. After general intelligence was partialled out, the Comprehension subtest related to some aspects of social functioning, but the clinical significance of this was limited. The Picture Arrangement subtest was unrelated to social functioning, once general intelligence was controlled. These findings were consistent across study groups.     

Factor structure and sex differences on the Wechsler Preschool and Primary Scale of Intelligence in China, Japan and United States

This study presents data on the factor structure of the Wechsler Preschool and Primary Scale of Intelligence (WPPSI) and sex and cultural differences in WPPSI test scores among 5- and 6-year-olds from China, Japan, and the United States. Results show the presence of a verbal and nonverbal factor structure across all three countries. Sex differences on the 10 subtests were generally consistent, with a male advantage on a subtest of spatial abilities (Mazes). Males in the Chinese sample obtained significantly higher Full Scale IQ scores than females and had lower variability in their test scores. These observations were not present in the Japan and United States samples. Mean Full Scale IQ score in the Chinese sample was 104.1, representing a 4-point increase from 1988 to 2004.