The PPVT-R as a measure of psycholinguistic functioning: a caution

The present investigation was undertaken to evaluate the use of the PPVT-R as a measure of psycholinguistic functioning. The sample included 75 school-aged children referred for evaluation. The mean PPVT-R standard score (94.59, SD = 15.85) was not significantly different (p less than .01) than the WISC-R Full Scale IQ (95.36, SD = 16.29), Verbal IQ (94.36, SD = 16.17), or Performance IQ (97.75, SD = 15.61), or the mean ITPA PLQ. The PPVT-R correlated positively and significantly with the WISC-R Full Scale IQ (.77), Verbal IQ (.71) and Performance IQ (.74) and the WISC-R subtests, with coefficients that ranged from .42 (object assembly) to .69 (vocabulary). In addition, the PPVT-R correlated positively and significantly with the ITPA Psycho-Linguistic Quotient (PLQ) (.72) and the ITPA) subtests, with coefficients that ranged from .38 (auditory sequential memory) to .72 (grammatic closure). Regression analyses determined that the ITPA PLQ and the PPVT-R standard score were not predictive of one another. The data are interpreted to suggest that the PPVT-R is not more appropriately used as a measure of receptive language ability than as a screen for intellectual functioning.     

Comparison of the WISC-R and PPVT-R with Navajo children

Explored the relationship between the Wechsler Intelligence Scale for Children-Revised (WISC-R) and the Peabody Picture Vocabulary Test-Revised (PPVT-R) for a sample of Native American children who reside on the Navajo Reservation. The sample consisted of 37 children aged 6 to 12−4 (M = 8−9, SD = 1−10). The PPVT-R standard scores correlated significantly (p < 0.001) with the WISC-R Verbal IQ (0.87). Performance IQ (0.52), and Full Scale IQ (0.82). The mean PPVT-R standard score was significantly lower (p < 0.001) than all of the mean WISC-R IQ scores. Implications of these findings for the use of the PPVT-R are discussed.     

Comparison of the PPVT-R and WAIS-R in state hospital psychiatric patients

This study examined the relationship between the Peabody Picture Vocabulary Test-Revised (PPVT-R) and Wechsler Adult Intelligence Scale-Revised (WAIS-R) in 40 adult psychiatric inpatients. The tests were administered to the patients in counterbalanced order as part of their overall psychological evaluation. Mean scaled scores were obtained for both tests. There were no significant differences between PPVT-R scores and WAIS-R Verbal, Performance, and Full Scale IQ scores. Significant correlations between the PPVT-R and all three WAIS-R scores also were obtained. However, further analysis indicated a great deal of variability between individual PPVT-R and WAIS-R Full Scale scores. In addition, the PPVT-R was found to underestimate significantly the WAIS-R IQ scores of a subgroup (N = 13) of mildly mentally retarded subjects. A tendency for the PPVT-R to overestimate the WAIS-R as IQ improved also was noted.     

The Slosson Intelligence Test and young learning-disabled children: a comparative study

Evaluated 26 children independently diagnosed as learning disabled in a counterbalanced design with the deviation IQ form of the Slosson Intelligence Test and the Wechsler Intelligence Scale for Children-Revised (WISC-R). Moderate to good correlations were obtained between the Slosson and the WISC-R Full Scale (r = .91), Verbal (r = .94) and Performance (r = .60) IQ scores. The Slosson correctly predicted functioning level to within 10 IQ points of WISC-R Full Scale scores for 88% of the Ss. These data suggest that the recent revision of the Slosson has corrected the tendency of earlier versions of this instrument to inflate the estimated IQs of young learning-disabled children.     

A preliminary study of black and white differences on the revised Wechsler intelligence scale for children

Investigated the performance of black and white children and youth on the WISC-R. The sample consisted of 120 Ss who were matched on the basis of their Full Scale WISC-R IQ score. Black males were matched with white males and black females were matched with white females, with 30 in each individual sample. The mean M.A. for the females was 10.6 and 10.0 for the males. Ss were matched in terms of Full Scale IQ. The Sander A statistical method was employed to analyze the data, and comparison of subtest scores between sexes was made by using the t-test for independent data. Evidence from the investigation indicates that the combined black sample performed better on the WISC-R Verbal Scale than did the white sample. Black males obtained significantly higher scores on Information and obtained higher scores on the four remaining Verbal scale subtests than did the white males. No differences were found between the females with regard to subtest scores. These findings did not support previous research that suggests that blacks tend to do more poorly on the Verbal area tests than on Performance tests of the WISC-R.     

Stability of WISC-R scores in a juvenile forensic sample

The temporal stability of WISC-R IQ Scale and subtest scores was examined in a Juvenile Court sample comprised primarily of neglected youth (N = 36). Stability coefficients were calculated for an average test-retest span of more than 2 years. WISC-R IQ Scale subtest scores were found to be stable to a degree comparable with WISC-R standardization data despite the considerably longer test-retest interval. Stability coefficients were .88 for Verbal IQ, .86 for Performance IQ, and .93 for Full Scale IQ. Subtest stability coefficients range from .49 to .82; many coefficients are equal to or greater than .70. No practice effects were apparent.     

A comparison of the WISC and WISC-R on hispanic children

Administered the WISC and the WISC-R in a counterbalanced design to 20 Hispanic children. Ss scored significantly lower on the WISC-R on Similarities, Object Assembly, Coding, and Mazes subtests, which resulted in lower Performance and Full Scale IQs. WISC-R scores tended to increase after practice on the WISC, but WISC scores tended to decrease after practice on the WISC-R. There was an overall difference of approximately 14 points between the Verbal and the Performance IQs on both tests. The only sex difference occurred on the Coding subscale; girls' mean score was higher than boys'. The tests were highly correlated. Important implications are that the WISC-R is as culturally biased as the WISC and that more Hispanic children may be labeled as mentally deficient. It is suggested that the Verbal IQ reflects the extent of acculturation, while the Performance IQ reflects actual ability.     

The reliability of score differences on the WAIS,WISC-R,and WAIS-R

Analyzed data from the WAIS, WISC-R, and WAIS-R manuals to determine the reliabilities of the differences between Verbal and Performance IQs, of subtest comparisons, and of differences between subtest and IQ scores. The differences between the Verbal and Performance IQs were moderately reliable: 0.76 (WAIS and WISC-R) and 0.81 (WAIS-R). The means of the reliability coefficients of the differences between the 55 pairs of subtests were appreciably lower: 0.58 (WAIS), 0.62 (WISC-R), and 0.65 (WAIS-R). The most consistently reliable subtest differences were between Block Design and Vocabulary and the least reliable differences between Block Design and Object Assembly. The means of the reliability coefficients of the differences between subtest scores and the Full Scale IQs were 0.53 (WAIS), 0.58 (WISC-R), and 0.62 (WAIS-R). It was concluded that caution should be exercised when interpreting configurations on Wechsler protocols.     

Correlation between intelligence test scores and executive function measures.

In this study, some executive function measures (Wisconsin Card Sorting Test [WCST], verbal fluency, and Trial Making Test [TMT], Form A and Form B) were correlated with Wechsler Intelligence Scale for Children-Revised (WISC-R) scores. Fifty 13- to 16-year-old normal children were selected. It was found that verbal fluency tests correlated about 0.30 with Verbal Intelligence Quotient (IQ) and Full Scale IQ. In the WCST only Perseverative Errors negatively correlated with Verbal IQ and Full Scale IQ. Two correlations were found to be significant with regard to the TMT: TMT Form B Errors negatively correlated with WISC-R Vocabulary subtest; and TMT Form A Time negatively correlated with Performance IQ. These results support the assumption that traditional intelligence tests are not appropriately evaluating executive functions.     

The relationship of the WISC-R to academic achievement in a clinical population

Investigated the validity of the WISC-R as a predictor of academic achievement in a population of emotionally disturbed adolescents (N = 35). Correlations and regression equations were derived between the WISC-R and two standardized measures of academic achievement, the PIAT and Woodcock. Verbal and Full Scale IQ estimates correlated at significant levels with the achievement measures used, and Verbal IQ estimates were the best single predictor of achievement. Performance IQ estimates were the least predictive and, as joint predictors, did not add any unique predictability. In comparison to the PIAT where Verbal IQ estimates were the best predictors, results for the Woodcock show that Verbal and Full Scale estimates make comparably significant predictors. Results support the predictive validity of the WISC-R for a clinical population and the continued use of this instrument in assessment batteries.     

A comparison of the Wechsler Intelligence Scale for Children-Revised and Leiter International Performance Scale for a group of educationally handicapped adolescents

Compared the WISC-R and Leiter International Performance Scale IQs for a sample of 42 educationally handicapped adolescents, who ranged in age from 13.1 to 16.5 years. Pearson product-moment correlation coefficients and correlated t-values were computed for the data analyses. The results indicated a pattern of positive correlations between WISC-R Verbal, Performance, and Full Scale scores and Leiter scores. WISC-R Verbal, Performance, and Full Scale IQs were found to be significantly higher than Leiter IQs. The findings suggest the generally the same pattern exists for the WISC-R and Leiter as for the WISC and Leiter.     

Cognitive profiles and the spectrum of clinical manifestations in heterozygous fra (X) females

We investigated the possibility that fra(X) heterozygotes had a distinct or specific set of mental deficits ("cognitive profile") which would allow for accurate diagnosis. Wechsler Intelligence Scale for Children-Revised (WISC-R) subtest scores obtained on 8 fra(X) school age girls were compared with similar scores obtained on 8 "learning-disabled" non fra(X) girls matched on the basis of Full Scale IQ (FSIQ). The Block Design subtest score was significantly lower in fra(X) girls. In a larger sample of 22 fra(X) females, a characteristic combination of low Arithmetic, Digit Span, and Block Design subtest scores was observed. The mean discrepancy between these 3 subtest scores from the total Verbal or Performance subtest means was significant for the fra(X) group but not for a comparison group of 20 learning-disabled females. Verbal IQ (VIQ) and Performance IQ (PIQ) discrepancy was not significant in fra(X) females. Percent fra(X) positive cells was negatively correlated with VIQ and FSIQ but not with PIQ.     

WISC-R stability and re-evaluation of learning-disabled students

This study investigated the temporal stability of WISC-R IQ scores for learning-disabled subjects (N = 113). All study subjects were administered the WISC-R for an initial evaluation (M age = 8 years, 3 months) and a follow-up re-evaluation (M age = 11 years, 7 months). Pearson product-moment correlations yielded coefficients that were considerably lower than those previously reported: r = .55, p less than .001 for the Verbal IQs; r = .63, p less than .001 for the Performance IQs; and r = .58, p less than .001 for the Full Scale IQs. Results of t-test analyses indicated that only the Verbal IQ scores were significantly different when the initial evaluation (M = 89.4) was compared to the re-evaluation (M = 85.3), p less than .001. The results suggest that the WISC-R may be less stable for the learning-disabled population than for other groups and that the average 3-year test-retest time lapse was an influential factor in the reduced reliability of this instrument.     

Comparison of the Kaufman Brief Intelligence Test and the Wechsler Intelligence Scale for Children-Third Edition in economically disadvantaged African American youth

The Kaufman Brief Intelligence Test (K-BIT; Kaufman & Kaufman, 1990) and the Wechsler Intelligence Scale for Children-Third Edition (WISC-III; Wechsler, 1991) are compared in 35 economically disadvantaged African American youth presenting for treatment in a community mental health setting. Significant correlations were found between K-BIT Composite and WISC-III Full Scale IQ scores. Results revealed significant differences between K-BIT and WISC-III scores; K-BIT Composite and Matrices mean scores were found to be 6 and 11 points higher than respective WISC-III Full Scale IQ and Performance IQ mean scores. No significant differences were obtained between K-BIT Vocabulary and WISC-III Verbal IQ scores. Our findings support the authors' recommendations for use of the Matrices subtest alone with African American youth from economically disadvantaged backgrounds (Kaufman & Kaufman, 1990).     

A WAIS longitudinal study of cognitive development during the life span from ages 50 to 70

A sample of 141 subjects born in 1914 was tested with the Wechsler Adult Intelligence Scale (WAIS) at the ages of 50, 60, and 70. Results showed a relatively moderate decline in test scores between successive examinations. For most subtests the decline was larger between 60 and 70 than between 50 and 60, and also larger for the Performance subtests than for the Verbal subtests (the total fall in Performance IQ was 7.2, and the total fall in Verbal IQ was 3.2). Seventy‐three males showed a larger decline than 68 females in Performance and Full‐Scale IQ, but the fall in test scores was not systematically related to educational background or initial IQ group. Further analysis provided evidence for a terminal drop hypothesis. The study demonstrated strikingly high retest stability of the WAIS IQ (a 20‐year retest coefficient of 0.90 for the Full‐Scale IQ).     

Concurrent validity of the Test of Nonverbal Intelligence with referred suburban and Canadian native children

The relationship between the Test of Nonverbal Intelligence (TONI) and the WISC-R was investigated for cultural differences. The samples consisted of 30 suburban and 22 Native children who were referred for learning difficulties. The results indicated the suburban group was higher than the Native group on Verbal IQ, but not Performance IQ, Full Scale IQ, or the TONI Quotient. The correlation coefficient between the TONI Quotient and PIQ was as expected in the Native group, but unexpectedly low in the suburban group. Implications of these findings for the testing of both referred majority and Native group members are discussed.     

A Yudin-type short form of the WISC-R: two aspects of validation

Provided validity data for a Yudin-type short form of the WISC-R for N equal to 70 middle-class children (34 males and 36 females, X age equal to 7.6 years, SD equal to 2.58 months) of above-average intelligence (means: VIQ equal to 115.55, PIQ equal to 122.27, FIQ equal to 121.02). Short- to long-form validity coefficients were all above .90 for Verbal, Performance, and Full Scale IQ scores. Highly similar predictive validity coefficients were found for the short and long forms of the WISC-R when compared with the Metropolitan Achievement and Otis Lennon Mental Ability tests. In contrast, little support was found for the validity of the short-form profile data as assessed by Cattell's rp coefficient of profile similarity.     

Comparison of various WISC-R summary scores for a psychiatric sample

Compared two sets of summary scores for the Wechsler Intelligence Scale for Children-Revised (WISC-R). The traditional scores used to summarize information about WISC-R performance (i.e., Verbal IQ (VIQ), Performance IQ (PIQ) and discrepancy between VIQ and PIQ) were compared to scores based on the three factors identified by Kaufman (1975) (i.e., Verbal Comprehension (VC), Perceptual Organization (PO) and Freedom from Distractibility (FD). Ss were 260 psychiatric outpatients who were administered the WISC-R during a 4-year period. The independent variables were sex and DSM II diagnosis. There were significant main effects for diagnosis for the VC and FD scales. There was a significant interaction for VIQ and nonsignificant results for the VIQ-PIQ discrepancy score. The groups did not differ in perceptual organization skills as assessed by PO and PIQ. Delinquents performed particularly poorly on the VC scale; hyperactive children had the highest VC score and relatively low scores on the FD factor; learning disabled children had low VC and FD scores. These findings suggest that the scores based on Kaufman's factors provided important clinical summary information that was not available from the traditional scores.     

Wechsler Adult Intelligence Scale and Wechsler Adult Intelligence Scale-Revised in a neurologically impaired population

Compared Verbal, Performance, and Full Scale IQ scores from two groups of neurologically impaired patients (N = 114) similar in age, years of education, occupation, race, sex, and etiology and location of cerebral dysfunction. One group had been given the WAIS and the other the WAIS-R. All three IQ scores were higher for the WAIS group, with Full Scale and Verbal scores significantly (p less than .05) higher. Changes in item content and standardization sample cohort effects are offered as partial possible explanation for the results. The IQ scores from the two tests cannot be considered as interchangeable for neurological patients.     

A comparison of black and white children's WISC/WISC-R differences

Administered the WISC and WISC-R to 20 white child psychiatric outpatients in a counterbalanced design. The white Ss' WISC/WISC-R differences were compared to equivalent data obtained from black children (Munford, 1978). For the white Ss, no differences were found between WISC and WISC-R Verbal, Performance, and Full Scale IQs, whereas black children scored significantly lower on the WISC-R than on the WISC on all three IQ measures. These findings indicate increased cultural bias in the WISC-R, despite apparent efforts to produce contrary results. A possible reason for this seemingly paradoxical outcome is offered, and future research possibilities are suggested.