A Comparison Of The Wechsler Intelligence Scale For Children Third Edition And The Wechsler Intelligence Scale For Children Fourth Edition

Abstract

There are no specific guidelines to determine when or why intelligence tests should be revised; however, revisions typically occur every 10 to 15 years to keep up with the moderate change in IQ over time, known as the Flynn effect (Flynn, 1984, 1987). Revisions also eliminate and update outdated items, content, and materials; extend age ranges, floors, and ceilings; as well as incorporate new theoretical changes. To assess cognitive abilities the Wechsler Scales are frequently used by clinical and school psychologists. Previous studies comparing versions of the Wechsler Intelligence Scale for Children (WISC) found significant correlations (.80s and .90s) and significant mean differences with the older version having higher scores than the newer version, providing evidence for the Flynn effect. The purpose of the current study was to examine the comparability ofthe WISC-III (Wechsler, 1991) and the WISC-IV (Wechsler, 2003) as well as find evidence of the Flynn effect. Participants were 89 students with Individualized Education Plans who underwent special education reevaluations in which the WISC-III was used at Time 1 and the WISC-IV at Time 2. Scores were exanuned using Pearson product moment correlation analysis, and dependent t-tests for differences between means were conducted to examine the significance between scores. Results found statistically significant correlations between similar or identical scores except for the verbal-performance difference scores. Only the mean differences for the WISC-III and WISC-IV FSIQ and PSI were significant, providing evidence for the Flynn effect. Future research should look to replicate this study with a larger and more representative sample of the general population.

Date of Award	2010
Original language	American English
Awarding Institution	Eastern Illinois University
Supervisor	Gary Canivez (Supervisor)