Psychological Reports, 1992, 70, 83-88. O Psychological Reports 1992
USING THREE DIFFERENT TYPES OF ASSESSMENT DATA FOR DIAGNOSTIC PURPOSES ' LARRY D. MAYES AND HUBERT B. VANCE East Tennessee State University Summary.-This study investigated the performance of 38 learning disabled and 16 emotionally impaired children and youth on the Wechsler Intelligence Scale for Children-Revised, Wide Range Achievement Test-Revised, and Minnesota Percepto-Diagnostic Test-Revised. The ages of the children ranged from 8.4 to 16.7 years (M = 12.4, SD = 3.6). The findings suggest that discriminate functional analysis may be useful in the differential diagnosis process. Implications for dinicians are discussed.
Psychologists are often asked to help make decisions about placing clddren and youth in various special education programs when using various types of assessment data. However, Adelman (1978) observed that a large number of students with learning problems are often assigned more than one diagnostic label, particularly if diagnosis is shared by special educators, psychologists, and educational diagnosticians. This is especially likely when trying to distinguish a learning disabled student from an emotionally disturbed one. To differentiate diagnostic groups of children and youth based on test patterns (profiles) of various individuahzed ability measures (Dean, 1978) has led to criticism by various researchers (Clarizio & Veres, 1983; Kaufman, 1976, 1979; Sattler, 1988; Vance, 1981; Vance, Fuller, & Ellis, 1983; Vance & Singer, 1979; Vance, Wallbrown, & Blaha, 1978). Vance (1981) remarked that those who continued to use some pattern approach in differential diagnosis were performing "simply a mental gymnastic approach with little value." Clarizio and Veres (1983) stated "any school psychologist who uses WISC-R data to diagnose emotional handicaps should be advised that there is little or no useful information in the subtest pattern examined to aid in such diagnosis" (p. 412). Vance, et al. (1983) echoed Clarizio's remarks by indicating that the continued search for specific diagnostic patterns such as flat profiles or verbal-performance discrepancies to discriminate learning disabled from emotionally impaired children or learning disabled and emotionally impaired children from normal children is a relatively fruitless task. Fuller and Goh (1981) employed a different methodological approach to investigate the differential diagnosis of learning disabled from emotionally handicapped children. They analyzed multitest scores from a comprehensive battery of intellectual, visuomotor, and achievement tests. Their discriminant function analysis indicated that it is possible to differentiate the groups 'Requests for reprints should be mailed to Hubert B. Vance, P O Box 23, OSOA, East Tennessee State University, Johnson City, TN 37601-0002.
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of chddren at an 83% "hit rate" by evaluating their performance on the Wechsler Intelligence Scale for Children-Revised (WISC-R) (Wechsler, 1974), Wide Range Achievement Test-Revised (WRAT-R) (Jastak & Jastak, 1969), and the Minnesota Percepto-Diagnostic Test-Revised (Fuller, 1982). The purposes of this study were (I.) to evaluate the correlations among these psychometric measures and (2) to estimate the "hit rate" for a differential diagnosis of learning disabled from emotionally handicapped children, by using their scores on the WISC-R, WRAT-R, and Minnesota Percepto-Diagnostic Test-Revised.
METHOD Subjects The sample of 75 children and youth ranged from 8.4 to 16.7 yr. of age (M = 12.4, SD = 7.6). Of these, 20 were girls and 55 were boys, and all subjects resided in Michigan. Out of the original pool of 75 children, 54 met the Michigan State Department of Education criteria (1986) for diagnosis as learning disabled or emotionally impaired. The ethnic composition of the original sample was 31 black, 40 white, and 4 Native American children. The reason for psychological evaluation included poor academic progress, behavior problems, learning difficulties, and poor school attendance. All were initial evaluations. Achievement data were compiled except for the mathematics portion of the WRAT-R (N = 26). Table 1 below presents the ranges, means, and standard deviations for (1) age, (2) WISC-R Verbal, Performance, and Full Scale IQs, (3) Minnesota Percepto-Diagnostic Test-Revised T scores, and (4) WRAT-R Spelling, Reading, and Mathematics grade-equivalent scores. Test Materials The test materials included were the Minnesota Percepto-Diagnostic Test-Revised (Fdler, 1982), WRAT-R (Jastak & Jastak, 1969), and the WISC-R (Wechsler, 1974). On Fuller's test, two Wertheimer designs, the circle and diamond, and the four rows of dots appear in three different orientations each (i.e., vertically on a diamond card, horizontally on a diamond card, and vertically on an oblong card). The subjects were instructed to copy each of the six stimulus figures on one piece of white paper. The norming population for this test included 4,000 children, ranging from 5 to 10 years of age, who were drawn from eight states. Interscorer reliabilities ranged from .88 to .94. The drawings were scored for amount of rotation and raw scores were converted to T scores, adjusted for both I Q and age. The T scores have been useful in differential diagnosis and as supplementary information for remedial teaching strategies (Vance, 1981; Vance, et al., 1983). The WISC-R
85
ASSESSMENT: TYPES O F DATA AND CLASSIFICATION
was chosen to evaluate intelligence, supplementing the rotation score. The WRAT-R provided measures of academic performance, and the Minnesota Percepto-Diagnostic Test-Revised estimated perceptual-motor skill. Procedure Subjects were individually administered the three tests in counterbalanced order by certified school psychologists who had been trained in administration of the tests. All protocols were checked carefully for possible scoring errors. Of the original 75 children, 54 were in the final data analysis because they met the State of Michigan Department of Education's criteria for being learning disabled (38) or emotionally impaired (16). The former group included 22 boys and 16 girls while the emotionally impaired sample consisted of 12 boys and 4 girls. The data were analyzed using a complete randomized two-way analysis of variance (test scores by sex and diagnostic group) with independent t tests to evaluate the differences between the mean scores. In addition, Pearson's correlation coefficients were calculated and the data were subjected to discriminant functional analysis.
RESULTS AND DISCUSSION The two-way analysis of variance for the WISC-R Verbal, Performance, and Full Scale IQs by sex and diagnostic group indicated that the girls scored lower than boys on the Full Scale IQ within the emotionally impaired group (F,,>,= 7.75, p < .008) but not within the learning disabled group. No significant difference was found between groups or the sexes for the WISCR Verbal IQs. The two-way analysis of variance yielded significant results between the two sexes (F,,,, = 8.66, p < .005) and the interaction of sex by group (F,,,, = 7.12, p < .010). Girls scored lower than boys (t,, = 2.50, p < .05) TABLE 1 RANGES, MEANS,AND STANDARD DEVIATIONS FORTHE TOTALSAMPLEBY D I A G N O SGROUP ~C Test Variable Range
All Subjects M
SD
Learning Disabled
M Age, yr. WISC-R Verbal IQ Performance IQ Full Scale IQ WRAT-R Spelling Reading Arithmetic MPDT-Score N
Emotionally Disturbed
p p
SD
M
SD
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L. D. MAYES & H. B. VANCE
within the emotionally impaired group but not within the learning disabled group. Based on this interaction we cannot say much about the main effects of sex or group on WISC-R IQs. The interaction (null hypothesis) is that the effect of group (learning disabled or emotionally impaired) is not a function of sex or vice versa. The two-way analysis of variance of T scores on rotation of drawing by sex and by group yielded no significant differences between the sexes (F,,,, = .31); however, because the sizes of the groups were very small, these results should be viewed with caution. Since the interaction was significant for the WISC-R Performance and WISC-R F d Scale IQs for the 4 emotionally impaired girls versus 12 emotionally impaired boys, we reject the null hypothesis and conclude that sex and group are not independent. However, as the sample was extremely small, these results should be viewed with caution. Table 2 presents the Pearson correlations among the three tests. Moderate to strong correlations were found among WRAT-R IQs (rs = .52 to .90, respectively). A moderate positive correlation was obtained between the Minnesota Percepto-Diagnostic Test-Revised and the WISC-R Verbal IQs (Y = .69, p< .001). Significant negative correlations were obtained between the Mimesota Percepto-Diagnostic Test-Revised and WISC-R Performance (T = - 3 3 , p < .01) and the WISC-R Full Scale ( r = -.68, p
USING THREE DIFFERENT TYPES OF ASSESSMENT DATA FOR DIAGNOSTIC PURPOSES ' LARRY D. MAYES AND HUBERT B. VANCE East Tennessee State University Summary.-This study investigated the performance of 38 learning disabled and 16 emotionally impaired children and youth on the Wechsler Intelligence Scale for Children-Revised, Wide Range Achievement Test-Revised, and Minnesota Percepto-Diagnostic Test-Revised. The ages of the children ranged from 8.4 to 16.7 years (M = 12.4, SD = 3.6). The findings suggest that discriminate functional analysis may be useful in the differential diagnosis process. Implications for dinicians are discussed.
Psychologists are often asked to help make decisions about placing clddren and youth in various special education programs when using various types of assessment data. However, Adelman (1978) observed that a large number of students with learning problems are often assigned more than one diagnostic label, particularly if diagnosis is shared by special educators, psychologists, and educational diagnosticians. This is especially likely when trying to distinguish a learning disabled student from an emotionally disturbed one. To differentiate diagnostic groups of children and youth based on test patterns (profiles) of various individuahzed ability measures (Dean, 1978) has led to criticism by various researchers (Clarizio & Veres, 1983; Kaufman, 1976, 1979; Sattler, 1988; Vance, 1981; Vance, Fuller, & Ellis, 1983; Vance & Singer, 1979; Vance, Wallbrown, & Blaha, 1978). Vance (1981) remarked that those who continued to use some pattern approach in differential diagnosis were performing "simply a mental gymnastic approach with little value." Clarizio and Veres (1983) stated "any school psychologist who uses WISC-R data to diagnose emotional handicaps should be advised that there is little or no useful information in the subtest pattern examined to aid in such diagnosis" (p. 412). Vance, et al. (1983) echoed Clarizio's remarks by indicating that the continued search for specific diagnostic patterns such as flat profiles or verbal-performance discrepancies to discriminate learning disabled from emotionally impaired children or learning disabled and emotionally impaired children from normal children is a relatively fruitless task. Fuller and Goh (1981) employed a different methodological approach to investigate the differential diagnosis of learning disabled from emotionally handicapped children. They analyzed multitest scores from a comprehensive battery of intellectual, visuomotor, and achievement tests. Their discriminant function analysis indicated that it is possible to differentiate the groups 'Requests for reprints should be mailed to Hubert B. Vance, P O Box 23, OSOA, East Tennessee State University, Johnson City, TN 37601-0002.
84
L. D.MAYES & H.B. VANCE
of chddren at an 83% "hit rate" by evaluating their performance on the Wechsler Intelligence Scale for Children-Revised (WISC-R) (Wechsler, 1974), Wide Range Achievement Test-Revised (WRAT-R) (Jastak & Jastak, 1969), and the Minnesota Percepto-Diagnostic Test-Revised (Fuller, 1982). The purposes of this study were (I.) to evaluate the correlations among these psychometric measures and (2) to estimate the "hit rate" for a differential diagnosis of learning disabled from emotionally handicapped children, by using their scores on the WISC-R, WRAT-R, and Minnesota Percepto-Diagnostic Test-Revised.
METHOD Subjects The sample of 75 children and youth ranged from 8.4 to 16.7 yr. of age (M = 12.4, SD = 7.6). Of these, 20 were girls and 55 were boys, and all subjects resided in Michigan. Out of the original pool of 75 children, 54 met the Michigan State Department of Education criteria (1986) for diagnosis as learning disabled or emotionally impaired. The ethnic composition of the original sample was 31 black, 40 white, and 4 Native American children. The reason for psychological evaluation included poor academic progress, behavior problems, learning difficulties, and poor school attendance. All were initial evaluations. Achievement data were compiled except for the mathematics portion of the WRAT-R (N = 26). Table 1 below presents the ranges, means, and standard deviations for (1) age, (2) WISC-R Verbal, Performance, and Full Scale IQs, (3) Minnesota Percepto-Diagnostic Test-Revised T scores, and (4) WRAT-R Spelling, Reading, and Mathematics grade-equivalent scores. Test Materials The test materials included were the Minnesota Percepto-Diagnostic Test-Revised (Fdler, 1982), WRAT-R (Jastak & Jastak, 1969), and the WISC-R (Wechsler, 1974). On Fuller's test, two Wertheimer designs, the circle and diamond, and the four rows of dots appear in three different orientations each (i.e., vertically on a diamond card, horizontally on a diamond card, and vertically on an oblong card). The subjects were instructed to copy each of the six stimulus figures on one piece of white paper. The norming population for this test included 4,000 children, ranging from 5 to 10 years of age, who were drawn from eight states. Interscorer reliabilities ranged from .88 to .94. The drawings were scored for amount of rotation and raw scores were converted to T scores, adjusted for both I Q and age. The T scores have been useful in differential diagnosis and as supplementary information for remedial teaching strategies (Vance, 1981; Vance, et al., 1983). The WISC-R
85
ASSESSMENT: TYPES O F DATA AND CLASSIFICATION
was chosen to evaluate intelligence, supplementing the rotation score. The WRAT-R provided measures of academic performance, and the Minnesota Percepto-Diagnostic Test-Revised estimated perceptual-motor skill. Procedure Subjects were individually administered the three tests in counterbalanced order by certified school psychologists who had been trained in administration of the tests. All protocols were checked carefully for possible scoring errors. Of the original 75 children, 54 were in the final data analysis because they met the State of Michigan Department of Education's criteria for being learning disabled (38) or emotionally impaired (16). The former group included 22 boys and 16 girls while the emotionally impaired sample consisted of 12 boys and 4 girls. The data were analyzed using a complete randomized two-way analysis of variance (test scores by sex and diagnostic group) with independent t tests to evaluate the differences between the mean scores. In addition, Pearson's correlation coefficients were calculated and the data were subjected to discriminant functional analysis.
RESULTS AND DISCUSSION The two-way analysis of variance for the WISC-R Verbal, Performance, and Full Scale IQs by sex and diagnostic group indicated that the girls scored lower than boys on the Full Scale IQ within the emotionally impaired group (F,,>,= 7.75, p < .008) but not within the learning disabled group. No significant difference was found between groups or the sexes for the WISCR Verbal IQs. The two-way analysis of variance yielded significant results between the two sexes (F,,,, = 8.66, p < .005) and the interaction of sex by group (F,,,, = 7.12, p < .010). Girls scored lower than boys (t,, = 2.50, p < .05) TABLE 1 RANGES, MEANS,AND STANDARD DEVIATIONS FORTHE TOTALSAMPLEBY D I A G N O SGROUP ~C Test Variable Range
All Subjects M
SD
Learning Disabled
M Age, yr. WISC-R Verbal IQ Performance IQ Full Scale IQ WRAT-R Spelling Reading Arithmetic MPDT-Score N
Emotionally Disturbed
p p
SD
M
SD
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L. D. MAYES & H. B. VANCE
within the emotionally impaired group but not within the learning disabled group. Based on this interaction we cannot say much about the main effects of sex or group on WISC-R IQs. The interaction (null hypothesis) is that the effect of group (learning disabled or emotionally impaired) is not a function of sex or vice versa. The two-way analysis of variance of T scores on rotation of drawing by sex and by group yielded no significant differences between the sexes (F,,,, = .31); however, because the sizes of the groups were very small, these results should be viewed with caution. Since the interaction was significant for the WISC-R Performance and WISC-R F d Scale IQs for the 4 emotionally impaired girls versus 12 emotionally impaired boys, we reject the null hypothesis and conclude that sex and group are not independent. However, as the sample was extremely small, these results should be viewed with caution. Table 2 presents the Pearson correlations among the three tests. Moderate to strong correlations were found among WRAT-R IQs (rs = .52 to .90, respectively). A moderate positive correlation was obtained between the Minnesota Percepto-Diagnostic Test-Revised and the WISC-R Verbal IQs (Y = .69, p< .001). Significant negative correlations were obtained between the Mimesota Percepto-Diagnostic Test-Revised and WISC-R Performance (T = - 3 3 , p < .01) and the WISC-R Full Scale ( r = -.68, p
