A longitudinal study of the Wechsler Intelligence Scale for Children-Revised

Abstract

The purpose of this study was to determine the long-term stability of the Verbal, Performance, and Full Scale IQ scores for the Wechsler Intelligence Scale for Children-Revised (WISC-R). Also under investigation was the longitudinal stability of scaled subtest scores and of the cluster scores delineated by Kaufman (1979). Results of the study supported the hypothesis that there would be no statistical difference between the Full Scale and Verbal IQ scores between Trial 1 and Trial 2 for the main group. However, significant changes were observed in Performance IQ and subtest scores. There were also statistical differences between Verbal, Performance, and Full Scale IQ scores for the ancillary group. No significant changes were noted in cluster scores. It was concluded that the Full Scale IQ score obtained from the WISC-R remains stable over the three year time period used for the main group in this study. This measure can be used with confidence by practitioners in placement decisions. Minor fluctuations were noted in Verbal IQ scores, while Performance IQ scores increased significantly between Trial 1 and Trial 2. Caution should be exercised when using these scores for programming purposes. Subtest scores varied considerably between the two trials. This should be taken into consideration when examining profiles of ability. If subtest scores are to be used, they should be combined into cluster groups. Cluster scores, as delineated by Kaufman (1979) remained stable over time.