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PsycholoRy in rhe Schools Volume 30, January I993

SUBTEST SCATTER AND KAUFMAN REGROUPINGS ON THE WISC-R IN NON-LEARNING-DISABLED AND LEARNING-DISABLED CHILDREN

TERESA SMITH, BILLY SMITH, NANCY MATTHEWS, AND SANDY KENNEDY

Universify of Cenfral Arkansas

The present study was undertaken to examine scatter analysis and Kaufman regroupings of WISC-R scores. Thirty-one non-learning-disabled children (NLD) and 29 learning- disabled children (LD) determined by individual IQ and achievement scores served as subjects. Scatter indices were computed within the Verbal and Performance subtests as well as between the Verbal and Performance IQ scales. Also, the regrouping cate- gories proposed by Kaufman (1979) were examined. A significant difference in Verbal and Performance IQs was found between the LD and NLD group. Significantly more students in thc LD group exhibited the Kaufman regrouping pattern than in the N1.D group (p< .01). These results suggest that Kaufman regroupings and Verbal-Per- formance scatter analysis may be used to assist in diagnosing LD children.

It has been estimated that public school children in the United States are required to take “more than 250 million standardized tests each year” (Salvia & Ysseldyke, 1988, p. 4). Three to five percent of all school children are referred for individual assessment on a yearly basis (Algozzine, Christenson, & Ysseldyke, 1982). Information about assess- ment instruments used in evaluations becomes critical because the test results are a major factor in determining eligibility for educational programs such as special education. These decisions frequently have a permanent effect on the child’s educational future.

One common factor that evaluations share is the use of an IQ test to determine the intellectual level of the child. The WISC-R (Wechsler, 1974) is one of the most widely used intelligence tests, and examiners frequently interpret subtest scatter and other factors as having clinical significance. It was originally assumed that an average child would have a “flat” (scatter in the subtest scores) profile. However, Kaufman (1976) demon- strated that “normal” children exhibit subtest scatter that ranges from 5 to 9 points between the highest and lowest scores. He then challenged the use of subtest scatter in the differentiation of learning-disabled children from normal children. Later, in a

This study was funded in part by the University of Central Arkansas Research Council. Requests for reprints should be sent to Teresa Smith, Department of Psychology, University of Central

Arkansas, Conway, AR 72032.

WISC-R Scatter and Kaufman Regroupings 25

review of the literature on subtest scatter found in profiles of learning-disabled children, Kaufman (1 98 1) concluded that: “Contrary to existing stereotypes about children with learning disabilities, this group does not seem to be characterized by abnormal scatter in their WISC-R profiles” (p. 523).

Cutkin (1979) analyzed the WISC-R Verbal-Performance difference, FSIQ (Full Scale IQ), VIQ (Verbal IQ), and PIQ (Performance IQ) scatter indices of 101 verified special education students, and found that these measures did discriminate between different classifications of special education students. When he compared the special education students with the normative data (Kaufman, 1976), significant differences were found between the two groups on all of the indices except for the VIQ. However, further analyses revealed that 40% of the children in the normative group exhibited as much or more scatter than the average special education student on each of the scatter indices.

Naglieri (1982) examined the difference between LD, Educable Mentally Retarded (EMR), and normal students on the WISC-R and McCarthy Scales and compared them to the normative data (Kaufman, 1976). The normal group was comprised of students enrolled in regular classrooms who were not referred for an evaluation. No attempt was made to determine the achievement levels of the “normal” group. There was no signi- ficant difference between the LD and normal group Verbal-Performance means. How- ever, mean WISC-R Verbal-Performance discrepancies for Naglieri’s LD and normal groups were higher than for Kaufman’s normative group. Therefore, although the LD group appeared to evidence a WISC-R Verbal-Performance discrepancy and subtest scatter greater than that of the normative data (Kaufman, 1976), it did not manifest more scatter than the normal group.

In determining what constituted “normal” children, Kaufman ( 1 976) used all children in the standardization sample. Achievement scores were not available on these children, and the definition of normality was based entirely on inclusion in the standardization sample. Since estimates of the number of learning-disabled children in the population range from 3vo to as high as 30% (Adelman & Taylor, 1986), it is possible that some of the children in Kaufman’s study could have been LD. Therefore, it is difficult to deter- mine the extent to which the test scatter of LD children and other handicapped children would have affected the outcome of Kaufman’s study.

Only one study (Schmidt & Saklofske, 1983) used achievement test scores with IQ scores to define a normal sample; however, the authors used group scores and did not report the name of the test or actual scores. Their reports concurred with Kaufman’s conclusion that subtest scatter does not differ significantly between normal and LD children, although the LD group did show Performance>Verbal more often than the normal group.

Another area in which assessment professionals have utilized the WISC-R is the recategorization of subtest scores to aid in the diagnosis of learning disabilities. Subtest recategorizations showing clinical significance were proposed by Kaufman (1979) as follows: Reasoning vs. Recall, Long Stimuli vs. Brief Stimuli, Much Expression vs. Little Expression, and Meaningful Stimuli vs. Abstract Stimuli. Grossman and Calvin (1989) transformed the WISC-R subtest scores of 105 children referred for suspected learning problems into deviation quotients (mean of 100 and standard deviation of 15). Using the paired regroupings of Kaufman (1979), the means were compared and the patterns of Reasoning > Recall, Much Expression > Little Expression, and Meaningful Stimuli > Abstract Stimuli were found to be significant (p<O.OOol). Long Stimuli vs. Brief Stimuli was not significant.

26 Smith, Smith, Matthews, and Kennedy

Since there are no reported studies that have defined “normal” children using in- dividual achievement test scores in conjunction with IQ scores, this area warrants further investigation. The present study investigated test profiles of normal and LD children as defined by individually administered IQ and achievement tests. In addition, the Kauf- man patterns were analyzed to determine whether they differentiated learning-disabled children from normal children.

METHOD Subjects

The WISC-R and Wide Range Achievement Test-Revised (WRAT-R; Jastak & Wilkinson, 1984) were administered to 60 children between the ages of 6 and 15. The average age was 9 years, 10 months, with a standard deviation of 2 years, 7 months. Thirty-one non-learning-disabled (NLD) volunteers and 29 children referred for learn- ing problems who at the time of their initial evaluation were diagnosed as learning dis- abled (LD) served as subjects. They were chosen based on the following criteria: NLD’s reading achievement scores were less than 15 points from the FSIQ and LD’s reading achievement scores were more than 15 points below the FSIQ. FSIQs ranged from 90 to 119 for both groups. These ranges were chosen to ensure that the regroupings and scatter would not be influenced by extremes of FSIQ (Patchett & Stansfield, 1992). The NLD group had mean FSIQs of 105.10, VIQs of 104.45, and PIQs of 105.00. The LD group had an FSIQ of 98.14, a VIQ of 93.83, and a PIQ of 104.07. The average age of the NLD group was 9 years, 1 1 months, with a standard deviation of 2 years, 10 months. The average age of the LD group was 9 years, 8 months, with a standard devia- tion of 2 years, 3 months. There were 16 females and 15 males in the NLD group and 20 males and 9 females in the LD group. In the NLD group all the students were White, and in the LD group 27 students were White and 2 were Black. All students were from the same geographic area.

Procedure Subtest scatter was computed in the following manner: Verbal Scatter (VS) was

found by obtaining the difference between the highest and lowest verbal scores (excluding Digit Span). The Verbal Scatter Digit Span (VSDS) was found by obtaining the difference between the highest and lowest verbal scores including Digit Span. The Performance Scatter (PS) was found by obtaining the difference between the highest and lowest per- formance scores excluding Mazes. Verbal-Performance Scatter (VPS) was found by ob- taining the difference between the Verbal and Performance IQ scores. These scatter in- dices of the LD and NLD groups were compared using an independent t test.

The WISC-R subtest regrouping scores of both groups were obtained by computing the mean scaled score of the subtests associated with the categories proposed by Kaufman (1979): Reasoning (Similarities, Arithmetic, Comprehension) vs. Recall (Information, Vocabulary, Digit Span); Long Stimuli (Information, Arithmetic, Comprehension) vs. Brief Stimuli (Similarities, Vocabulary, Digit Span); Much Expression (Similarities, Vocabulary, Comprehension) vs. Little Expression (Information, Arithmetic, Digit Span); and Meaningful Stimuli (Picture Completion, Picture Arrangement, Object Assembly) vs. Abstract Stimuli (Block Design, Coding).

RESULTS The results indicated no significant differences between the groups on VS, t(58) =

0.674, p = 0.503), and no significant differences were found between groups on VSDS,

WISC-R Scatter and Kaufman Regroupings 27

t(57) = 1.299, p = 0.224. No significant differences were found in the two groups on PS, t ( 5 8 ) = 1 S 3 7 , p = 0.130. However, a significant difference was found between the LD group and NLD group on VPS, t (58 ) = 5.74, p = O.OO0. The alpha level for these t tests was corrected by the Bonferroni procedure (McGuigan, 1983).

Independent t tests were used t o analyze the Kaufman regroupings, with the results shown in Table 1 . For between-group comparisons, the NLD scores were significantly higher than the LD scores on all regroupings except Meaningful Stimuli and Abstract Stimuli. Meaningful Stimuli was the only subtest regrouping on which the LD group scored above the mean.

Table 1 t Test Results for the LD Group and NLD Group

Regrouping

Reasoning Recall Long Stimuli Brief Stimuli Much Expression Little Expression Meaningful Stimuli Abstract Stimuli

N LD LD

Within M SD 1

Within Between M SD 1 t

10.90 1.72 1.91 10.22 1.59 10.67 1.52 0.59 10.43 1.76 11.01 1.75 2.39 10.12 1.63 11.00 1.40 1.73 10.39 2.18

9.38 1.44 4.82' 8.23 1.32 9.15 1.48 2.19' 8.46 1.50 9.08 1 .51 1.88 8.53 1.40

11.07 1.40 2.95' 9.83 2.41

3.7!* 5.24* 3.91' 4.63' 4.56, 4.03* 0.19 0.95

~~

*Significant at .05 level, alpha level corrected by the Bonferroni procedure.

The within-group t tests yielded significant differences for Reasoning vs. Recall, Long Stimuli vs. Brief Stimuli, and Meaningful Stimuli vs. Abstract Stimuli regroup- ings in the LD group, with none of the regroupings significant in the NLD group. The scores in the NLD group followed the same pattern as the LD group; however, the differences in the scores were minimal and not significant.

The extent to which individuals in each group showed the Kaufman pattern (Reasoning > Recall, Much Expression > Little Expression, Long Stimuli >Brief Stimuli, and Meaningful Stimuli>Abstract Stimuli) was examined. It was found that only 10 of the 30 NLD students demonstrated a minimum of three of the patterns, whereas 22 of the 29 LD students demonstrated a minimum of three of the patterns. This com- parison was significant, ~ ' ( 1 , N = 59) = 10.75, p < .001.

DISCUSSION Differences were found between the NLD and LD groups on the Verbal-Performance

scales only. Subtest scatter was not significantly different in the two groups. As Kauf- man (1976) found, there seems to be scatter in normal as well as handicapped popula- tions. Since the NLD children were classified on IQ and achievement, thus ensuring that no LD children were inadvertently included in the normal group, it appears that scatter analysis will not be helpful in discriminating LD from NLD students. These results should help finalize the debate about the clinical usefulness of subtest scatter.

The finding of Verbal-Performance differences seems consistent with other studies (e.g., Schmidt & Saklofske, 1983) and indicates that LD children tend to have higher Performance scores than Verbal scores. In the present study, the LD children had

28 Smith, Smith, Matthews, and Kennedy

Performance scores that were substantially higher than their Verbal scores. These children were randomly selected from a pool of LD subjects with the restriction that only their FSIQ be in the range from 90 to 119. Therefore, it appears that a Verbal-Performance split may be indicative of the need for closer examination of the possibility of a learn- ing disability.

These results also suggest that there are differences between LD groups and NLD groups on the Kaufman regroupings. Analyzing test scores according to these patterns may have diagnostic value, although there may be greater validity in using the results to develop an effective remedial program (Kaufman, 1979). Since 22 of the 29 subjects in the LD group had Kaufman regrouping scores in the order expected (Reasoning> Recall, Much Expression > Little Expression, Long Stimuli > Brief Stimuli, and Mean- ingful Stimuli > Abstract Stimuli), this regrouping may be a diagnostic indicator. Therefore, when preparing Individual Educational Programs it would be beneficial to incorporate this pattern analysis into the development of teaching strategies for LD children. Furthermore, it should be noted that Meaningful Stimuli was the only group- ing in which the LD children scored above average. The perceptual areas incorporated into the Meaningful Stimuli grouping are often neglected in regular classroom teaching approaches, which rely heavily on verbal teaching strategies. By using these more con- crete channels, achievement scores of LD children may show more improvement.

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