A longitudinal comparison of WISC-III and WISC-R scores of special education students

Abstract

This study investigated the performance of 166 special education students who had been administered the WISC-R and approximately 3 years later the WISC-III. The sample ranged in age from 6.0 to 16.6 years. The scores were analyzed using Pearson product moment correlation coefficients and t tests of the differences between means for related samples. The results indicated that there was a significant, positive correlation among global scales (p < .001). This finding suggests that the WISC-R and the WISC-III IQ scores measure similar abilities. Analysis of mean IQ score differences revealed significant differences in the WISC-R and the WISC-III IQ scores, with the WISC-III global scores being lower. Implications for the evaluation of students for special education are discussed, with special emphasis on the role and function of the psychologist practicing in the schools. © 1996 John Wiley & Sons, Inc.