Measuring stability and change in WISC-R IQS

Webster (1988) assessed WISC-R IQ stability in samples of adolescents identified as EMR and LD. It is argued here that Webster used an inappropriate standard error of measurement in his study. This resulted in magnified estimates of the number of individuals who obtained significantly discrepant IQs from one test admnistration to the next. Webster's analyses therefore exaggerated the degree of test-retest instability inherent in WISC-R IQs.     

A comparison of the Slosson intelligence test and the WISC-R with elementary school children

The WISC-R and the Slosson Intelligence Test (SIT) were given to 69 randomly selected children in grades one through six in an urban school system. A regression equation for predicting WISC-R full scale IQ from SIT was developed. Previous studies had reported that SIT IQs tended to be consistently higher than WISC-R IQs. The present study revealed that SIT IQs were considerably higher than WISC-R IQs in the upper range and slightly lower in the lower range. A possible reason for the discrepancy is that the present study used a normal population and previous studies used restricted ranges. It was concluded that the SIT provides a good estimate of WISC-R full scale IQs when a regression equation is used. It was recommended, however, that educational placement decisions should not be made on the basis of any single IQ measure.     

Comparison of the slosson intelligence test,revised norms,and WISC-R for children with learning problems and for gifted children

The Slosson Intelligence Test (revised norms) (SIT) and the WISC-R were compared in two samples of children. In the first sample, there were 34 black and 27 white rural Southeastern Alabama children being considered for special education classes. In the second sample, there were 4 black and 81 white suburban Alabama children being considered for classes for the talented and gifted. In both samples, correlations between the SIT IQ and WISC-R Full Scale IQ were significant (rs of .70 and .48, respectively). However, in the special education sample, SIT IQs were significantly higher than WISC-R Full Scale IQs by about 7 points. The results from both samples provide a moderate degree of support for the concurrent validity of the revised SIT norms, using the WISC-R as the criterion. However, the IQs on the two tests may not be interchangeable.     

A longitudinal study of the Stanford-Binet and WISC-R with special education students

A group of 95 black and 52 white low socioeconimic children assigned to special education calsses were initially given the Stanford-Binet (1972 norms) and three years later the WISC-R. Correlations between the Stanford-Binet and WISC-R Full Scale IQs were significant in both ethnic groups, with r=.60 for the total group. Correlations between the Stanford-Binet and WISC-R subtests also were generally signiificant (rs between .29 and .52 for the total group). Stanford-Binet and WISC-R Full Scale IQs did not differ significantly. For this sample of special education children, the Stanford-Binet was found to have satisfactory predictive validity.     

Comparability of the WISC and the WISC-R in normal children of divergent socioeconomic backgrounds

WISC and WISC-R IQs of two groups of normal ten-year-old children from divergent socioeconomic backgrounds (N = 36) were compared in a counterbalanced research design. Generally, all WISC mean IQs were higher than the WISC-R mean IQs for both groups of children. Significantly higher WISC IQs were obtained on the Verbal and Full Scales of the low socioeconomic group and on the Performance and Full Scales of the high socioeconomic group. Correlations between tests for Verbal, Performance, and Full Scale IQs were.95,.79, and.91 for the low socioeconomic group, and.84,.57, and.87 for the high socioeconomic group. Although practice effects did not appear to significantly affect IQs of the low socioeconomic group, various practice effects were observed in the high socioeconomic group. Negative effects were observed for both WISC and WISC-R on the Verbal Scale, whereas positive effects were observed on both Performance and Full Scales in this group. Analysis of simple effects reveals that WISC and WISC-R IQs did not differ significantly upon first administration, but were significantly different upon second administration. Conclusions were drawn that while WISC-R yields a lower IQ estimate than WISC for children of lower ability, results were not so clear for the children of higher ability, due to practice effects which disproportionately favor increases on WISC IQs upon second administration. The greater practice effects found on the WISC have implications for comparisons of the two tests in counterbalanced research designs. Simple randomized or treatment-by-levels design may be more useful in comparisons of the WISC and the WISC-R because of the bias introduced by counterbalanced designs.     

Validity of WISC-R IQS and factor scores in predicting achievement for Mexican-American children

The predictive validity of the WISC-R IQs and factor scores was examined with a sample of 64 Mexican-American children. All the correlations among the WISC-R factor scores and academic achievement as measured by the Wide Range Achievement Test (WRAT) were found to be low, ranging from .09 to .31. Significant relationships were observed only between WRAT Reading and Perceptual Organization (PO) factor, WRAT Arithmetic and PO factor, and Freedom from Distractibility (FD) factor and WRAT Arithmetic scores. In contrast to this, however, significant relationships were observed between IQ scores and achievement measures, suggesting predictive utility of the WISC-R IQs in predicting achievement for Mexican-American children.     

Validation of the Stanford-Binet Intelligence Scale: Fourth edition with exceptional black male students

Standard Age Scores on the Stanford-Binet Intelligence Scale: Fourth Edition (SBIV) and WISC-R IQs of 51 urban black males receiving special education services were compared. Correlations between the SBIV Composite scores and WISC-R Verbal, Performance, and Full Scale IQs were 0.803, 0.826, and 0.87 respectively. Correlations between all combinations of scales ranged from 0.612 to 0.888, median r=.723. SBIV Composite mean scores did not differ significantly from the mean WISC-R Full Scale, Verbal, and Performance IQs. Regression analysis of the three subgroups (BD. LD, and EMR) indicated that the SBIV possesses differential validity for each group. Tabular comparison of precision of classification between the SBIV and the WISC-R yielded a 78% agreement. These data suggest that the SBIV possesses utility for assessing the intelligence of black students classified as BD and EMR. However, the use of the scale with LD students is unsupported.     

The role of sex differences in the referral process as measured by the Peabody Picture Vocabulary Test-Revised and the Wechsler Intelligence Scale for Children-Revised

The Peabody Picture Vocabulary Test-Revised (PPVT-R) and the Wechsler Intelligence Scale for Children-Revised (WISC-R) are two tests that are often used in the assessment process for special education referrals. Sex differences apparent in these tests were examined in a sample of Arkansas school children who were first-time referrals for a psychological evaluation. The subjects' PPVT-R standard scores, WISC-R IQ scores, and WISC-R subtest scores were divided into groups according to one-year intervals from ages 6 through 16. A separate 2 × 11 (subjects' sex x subjects' age) analysis of variance was performed for each dependent variable. Results indicated significant sex differences among WISC-R Full Scale, Verbal, and Performance IQs and PPVT-R standard scores (p < .01). Several WISC-R subtests also revealed significant sex differences. Further significant sex differences were indicated at several age groups on each dependent variable, with males consistently scoring higher than females on 87%. of the dependent measures excluding the WISC-R subtest Coding, on which females scored higher. Implications concerning the referral process are discussed.     

Relationship between PPVT and WISC-R in children with reading disabilities

The Peabody Picture Vocabulary Test (PPVT), Form A was compared to the Wechsler Intelligence Scale for Children-Revised (WISC-R) in two samples of children with reading disabilities. One group of 14 children, referred to a university clinic, were administered the WISC-R, followed by the PPVT. The second group of 38 children from a private learning disability center were administered the PPVT first, followed by the WISC-R. In the combined sample, the PPVT IQ (X̄ = 109.2) was significantly higher than the WISC-R Verbal IQ (X̄ = 98.9), Performance IQ (X̄ = 97.0), and Full Scale IQ (X̄ = 97.5). Similarly, the PPVT IQ was significantly higher than the WISC-R Full Scale in both samples separately, regardless of which test was administered first. In one case, the PPVT IQ was 50 points higher than the WISC-R IQ. Correlations between the PPVT and WISC-R Verbal, Performance, and Full Scale IQs were significant (rs = .56, .29, and .50, respectively). The results suggest that the two tests do not provide interchangeable IQs for a population of reading disabled children.     

Further investigation of comparability of the WISC-R and PPVT-R for children and youth referred for psychological services

Comparisons of the WISC-R and PPVT-R were made with 37 students (25 boys, 12 girls). Pearson product moments (r) and two-tail f-tests were employed in the data analysis. The sample ranged in age from 6-2 to 14-6, with a mean age of 10-1, and SD=2.6. There were no significant differences between the WISC-R IQs and PPVT-R standard scores. The PPVT-R did not correlate significantly with the WISC-R IQ scales.     

Discrepancies between IQ and index scores for a clinical sample of students: Useful diagnostic indicators?

Discrepancies between IQ and Index scores on the WISC-111 were investigated for a sample of students with SLD (n = 202), with MR (n = 115), and evaluated but not classified (n=159). Mean Verbal and Performance IQ discrepancies, though significantly different for each sample, were smaller than those reported in the WISC-III manual for the normative sample. Similarly, the Index score comparisons indicated differential functioning for the three samples, with the exception of the Verbal Comprehension and Freedom from Distractibility Index discrepancy. Moreover, the Performance IQ was higher than the Verbal IQ for all three samples. Consistent with the WISC-R literature, discrepancies between Verbal and Performance IQs and higher Performance than Verbal IQs are not diagnostic indicators of abnormalities.     

A longitudinal comparison of the WISC-R and WAIS-R

The degree of comparability between the WISC-R and WAIS-R over time was assessed for two samples of referred adolescents of borderline intelligence intially administered a WISC-R and retested on the WAIS-R after three years. Results indicated that the WAIS-R significantly overestimated the WISC-R IQs by 3 to 5 points. Differences were most marked at the lower ability levels; as IQs aproached average, scores were increasingly comparable.     

Screening for giftedness with the Slosson and the scale for rating behavioral characteristics of superior students

Children who had been nominated as potential candidates for gifted programs were assessed to determine the relationships among certain behavioral and intellectual characteristics. Records were compiled listing 132 first- through eighth-grade children's race, sex, age, grade level, Slosson Intelligence Test (SIT) IQ scores, Scale for Rating Behavioral Characteristics of Superior Students (SRBCSS) scores, and WISC-R IQs. Only children achieving SIT IQs of 130 or higher were included. A regression equation for the prediction of a WISC-R Full Scale IQ score from a given SIT score was computed and compared to that developed for predicting the WISC-R IQ in another study. All variables except SIT IQ were poor predictors of WISC-R IQ scores. A moderate correlation was computed between SIT and WISC-R Verbal and Full Scale IQ scores. A somewhat lower, but still significant, degree of relationship was found between SIT and WISC-R Performance IQ scores. Some difficulties with using the SIT as a screen for gifted programs are discussed.     

Similarity of WISC-R and WAIS-R scores at age 16

Thirty learning disabled students of average intellectual ability between 16 and 17 years of age were given both the WISC-R and the WAIS-R to determine if the WAIS-R provided higher average IQ scores, as had been reported for educationally mentally retarded adolescents. The results indicated: (a) no significant differences between the two scales on either the Verbal, Performance, or Full Scale IQs, (b) significant correlations between the WISC-R and WAIS-R on the three IQ scores and 9 of the 11 subtests, and (c) the emergence of the ACID profile for learning disabled adolescents on both tests.     

A longitudinal study of the WISC-R and WAIS-R with special education students

The relationship between the WISC-R and WAIS-R was studied in a sample of 30 special education children (22 male and 8 female). Children were administered the WISC-R at an average age of 13.85 years and the WAIS-R at an average age of 17.52 years. ANOVAs indicated that the two tests yielded Verbal, Performance, and Full Scale IQS that were not significantly different. For example, the mean Full Scale IQ was 81.13 for the WISC-R and 82.70 for the WAIS-R. Product-moment correlations also were highly significant, with rs ranging from .76 to .86 for the three scales. The results suggest that, for children of limited intelligence, the WISC-R and WAIS-R provide comparable IQs over a four-year time period.     

A comparison between the WISC and WISC-R among a clinical referred population

This study compared the three scales of the WISC and the WISC-R for degree of intercorrelation. The differences among scores and among variances were also computed for the two tests. Fifty-eight subjects from a clinical referred population were studied, including children classified as EMR, Learning Disabled, Emotionally Disturbed, and children in regular classrooms. Results included significant correlations in all cases, no systematic changes in variance, and significantly lower IQs on the WISC-R for all children in this sample, except the EMRs.     

Clinically and theoretically derived WISC-R subtest regroupings: Predicting academic achievement in a referral population

Attention continues to be directed toward the WISC-R as a tool for understanding children's learning problems. The formulation of WISC-R subtest regroupings (apart from the traditional Verbal, Performance, and Full Scale IQs, and the empirically derived factor scores) may provide a basis for score interpretation and the generation of hypotheses regarding children's cognitive strengths and weaknesses. The present investigation analyzed the predicitive utility of several WISC-R subtest recategorizations with regard to academic to achievement as measured by the WRAT. The sample consisted of 105 children who had been referred for psychoeducational evaluation because of classroom learning problems. Stepwise regression analyses indicated that many of the regroupings were significant predictors of academic achievement. Generated regression equations are presented.     

A comparison between the WISC and WISC-R among educable mentally retarded students

The study compared differences and similarities between WISC and WISC-R scores for 48 ten- and thirteen-year-old EMR students, who were matched according to sex and race. The WISC-R yielded significantly lower VS, PS, and FS IQ scores than the WISC for this predominantly rural Georgia population. The FS IQ scores from the WISC-R averaged 7.5 points lower than the WISC FS IQs, with similar differences noted for VS and PS scores. There was no significant difference in FS IQs between the two age groups. Results suggest that many children classified as “Borderline” or slightly above by the WISC will be classified as “Mentally Deficient” by the WISC-R.     

A comparison of the WISC and WISC-R

So as to compare the results of the WISC and WISC-R, both instruments were administered to 58 children randomly selected from a school population of 583. All administration and scoring was performed by the same psychologist, with a two-month interval separating the administrations for each child. All IQs were significantly higher (p <.01) on the WISC, with the Performance difference being greater than the verbal difference. Also, 8 of the 10 required subtest scaled scores were significantly greater (p <.05) on the older instrument. Regression equations were obtained to predict WISC-R IQs from WISC scores.     

Sex differences in the WISC-R scores of gifted students

This study is an investigation of the sex differences in the WISC-R scores of gifted students. The sample consisted of 946 students (479 males and 467 females), with a chronological age range of 6.0 to 16.0, and a mean CA of 9.9. The results indicated significant mean differences on several subtest scores and IQs, generally favoring males.