Incremental Validity Of Wisc-Iv Factor Scores In Predicting Academic Achievement On The Wiat-Ii

Abstract

This study examined the incremental validity of Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV; Wechsler, 2003) factor scores in predicting reading and math achievement on the Wechsler Individual Achievement Test-Second Edition (WIAT-11; Wechsler, 2002). Participants included K-12 students in a medium sized Midwestern school district who underwent an evaluation using the WISC-IV and the WIAT-II. Block entry multiple regression analyses were used to examine whether the WISC-IV factor scores substantially improved the prediction ofreading or math achievement on the WIAT-11 above and beyond the contribution made by the FSIQ. Results indicated that the WISC-IV FSIQ accounted for the majority of the variance in both reading and mathematics composite scores on the WIAT-II (34.3% and 55.7% respectively). In the prediction of reading achievement, the factor score indexes provided a statistically significant increment over the FSIQ, though the size of improvement (7.9%) was too small to be of clinical utility. In the prediction of math achievement, the factor scores did not provide a significant increment of prediction (1.1 %) above and beyond the FSIQ. This study indicated that the WISC-IV factor scores did not substantially increase the predictive validity beyond the WISC-IV FSIQ. Therefore, like other investigations (Glutting et al., 1997; Glutting et al., 2006; Watkins et al., 2007), psychologists only need to interpret the WISC-IV FSIQ when predicting reading or math performance on the WIA T-II.

Date of Award	2009
Original language	American English
Awarding Institution	Eastern Illinois University
Supervisor	Gary Canivez (Supervisor)