7 - Using the Woodcock-Johnson III Tests of Achievement with the WISC-III and WAIS-III to Determine a Specific Learning Disability

Abstract

This chapter throws the attention to determine a specific learning disability by using the Woodcock–Johnson III tests of achievement with the WISC-III and WAIS-III. Most psychological assessments completed in school systems are intended to substantiate learning difficulties evidenced in the classroom. Selection of the ability and achievement scales is an important decision for psychologists. The discrepancy is meaningless unless scores on a variety of intelligence and achievement tests are relatively equivalent and stable across time. The discrepancy model for determining a specific learning disability is fraught with debate. Nonetheless, a best-practices model dictates that grade-level differences should not be utilized for determining a learning disability because of the inherent variability across age groupings. Therefore, when assessment professionals choose not to use the WJ III COG together with the WJ III ACH, but instead select a different measure of cognitive functioning to combine with the WJ III ACH, utilization of a regression formula that corrects for regression to the mean and computes predicted achievement scores, is the most statistically sound practice. Although there is a paucity of data for math disorders, there is considerable empirically supported data regarding reading deficits. Finally, an evaluation of these critical competencies is essential for guiding subsequent intervention procedures.