Wechsler Individual Achievement Test - 2nd Edition

Purpose:  Designed to assess individual achievement.

Population:  Children, adolescents, college students, and adults, or age 4 through 85.

Scales:  Reading, Mathematics, Written and Oral Language, and 9 sub-test scores

Time:  45 minutes for Pre K-K, 90 min. Grades 1-6,  90 - 120 min. Grades 7-16

Author: David Wechsler.

Publisher: The Psychological Corporation

Description: The Wechsler Individual Achievement Test - Second Edition (WIAT-II) revises the Wechsler Individual Achievement Test (WIAT; The Psychological Corporation, 1992). The areas covered by the test remain the same, but the depth and range of subject matter has been increased, with some new items, and updates of content to reflect changes in curriculum standards ands incorporate cutting-edge research in the acquisition and assessment of educational skills Specifically, the Listening Comprehension and Oral Expression subtests have been modified to coincide with skills demanded of the student in the classroom. The Reading Comprehension subtest now includes questions geared to a greater level of understanding, and asses reading rate and oral reading. Phonological decoding has been added to evaluate "word attack" skills, and there are several ways to demonstrate writing skills.  An attempt has been made to establish a greater link between assessment and intervention by better analysis, which looks at both the product and the process involved in a skill. The age range of the WIAT has been extended in both directions including preschoolers for early assessment, and college students and adults in need of academic skills evaluation.

Scoring:  Scoring for the WIAT-II has been made more clear and consistent with instructional practice. Standard scores are by age or by grade, ( M=100, SD=15) with a range of 40 to 160 and seasonal tables for pre-K - 8.

Reliability:  Internal consistency reliability estimates of the WIAT-II subtests are generally high (above .85) with the exception of the Written Expression and Listening Comprehension subtests in the school-aged sample and the Written Expression and Oral Expression subtests in the college-adult sample. The reliability estimates of these subtests were only somewhat lower (above .70). Internal consistency reliability of the Composite scores was very high (above .90) in both samples with the exception of the Oral Language Composite, which was above .85. In the school-aged sample, test-retest correlations for the subtests (across intervals of approximately 10 days) were consistently above .85 and test-retest correlations for the Composite scores were above .90. Tests-retest correlations were somewhat lower in the college-adult sample, with correlations between .75 and .85 in Reading Comprehension, Written Expression, Oral Expression, and the composite scores for Written Language and Oral Language.

Validity:  The corresponding subtests of the WIAT and the WIAT-II are strongly correlated (above .80) in the school-aged sample for those subtests with minimal content changes. The correlations were lower for subtests that had changed the most: Reading Comprehension (r = .74), Written Expression (r = .48), Listening Comprehension (r = .68), and Oral Expression (r = .62) subtests. Although it is evident that the refined WIAT-II subtests are assessing academic skills in different ways than traditional achievement tests, it is not yet fully clear whether the WIAT-II's substantial content revisions will yield better, more usable indices of students' academic abilities

Norms:  The WIAT-II was standardized on 5586 individuals with two standardization samples drawn for PreK-12 (ages 4-19) and for the college-adult population. Both standardization samples were stratified on the basis of grade, age, sex, race-ethnicity, geographic region, and parent education level, based on the data from the 1998 Bureau of the Census.

Suggested use:  The WIAT-II is useful in schools, clinics, private practices and residential treatment facilities.  In conjunction with direct observation, history and additional measures the WIAT-II can assist with diagnosis, eligibility, placement, decisions regarding interventions.