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 x 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 @< .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.
An important factor in the assessment of children for special education is the observation of sex differences among referred populations. Koppitz (1975) indicated that males tend to be referred for psychological evaluation and treatment more often than females.
McGuinness (1985) also reported that approximately 75% of the students receiving remedial reading and special education services are males.
Two tests that are commonly used in psychoeducational diagnostic procedures are the Peabody Picture Vocabulary Test-Revised (PPVT-R) and the Wechsler Intelligence Scale for Children-Revised (WISC-R). Since the revision of the PPVT in 1981, only one study (Dunn and Dunn, 1981) has considered the aspect of sex differences in the scores. The only significant difference @< .05) was obtained from 15-year-oldsY tested on Form M, with males scoring higher. There was, however, a trend for males to score higher than females at 15 of the 21 age groups tested with Form L and at 16 of the 21 age groups tested with Form M. Brimer (1969), using an English version of the PPVT, found significant sex differences, with boys outperforming girls.
Males tend to score higher on the Wechsler scales, although the differences have been considered of little or no practical significance (Kaufman & Doppelt, 1976). Eno and Woehlke (1980), however, investigated WISC-R scores of 110 special education children and found that males scored significantly higher on Verbal, Performance, and Full Scale IQs.
The purpose of the present study was to explore sex differences on the PPVT-R and the WISC-R among school children from an initially referred population. Age levels at which these differences occur were also investigated. Because the WISC-R predicts school achievement (Smith and Smith, 1986) and the PPVT-R correlates with the WISC-R Verbal Scale (r= .78, p < .01, Hollinger and Sarvis, 1984), it was determined that these two tests were appropriate measures for the present study. A final aspect of this study Requests for reprints should be sent to Teresa C. Smith, Dept. of Psychology, Box 4915,