A 3-YEAR COMPARISON STUDY OF WISC-R AND WISC-III IQ SCORES FOR A SAMPLE OF SPECIAL-EDUCATION STUDENTS

The purpose of this study was to compare the Wechsler scores for the same group of students after a 3-year interval. A sample of 84 regular and special education students were tested first on the WISC-R and then 3 years later on the WISC-III. Scores were broken up into five score subgroups from lowest to highest. More WISC-III scores appeared in lower IQ ranges, whereas fewer WISC-III scores appeared in higher IQ ranges. It was surmised that the WISC-III was more difficult at the higher IQ ranges and less difficult at the lower IQ ranges. WISC-III Performance scores displayed more (lower) differences between administrations, whereas the Verbal scores, which were higher, showed more variability. Researchers concluded that practicing psychologists might be more inclined to place students in classes for the educable mentally retarded (EMR) based on the effects of lower Performance Scale scores than on Full Scale IQs.