A Validated Seven-Subtest Short Form for the WAIS-IV

Abstract

This study presents a short form of the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV; Wechsler, 2008) using the subtests (Block Design, Similarities, Digit Span, Arithmetic, Information, Coding, and Picture Completion) suggested by Ward (1990). These seven subtests were used to predict the full WAIS-IV Full-Scale IQ, as well as the Verbal Comprehension, Perceptual Reasoning, Working Memory, and Processing Speed Index scores. Two different data sets were used: the first consisted of 70 subjects and the second consisted of 32 subjects. The first data set was used to create a linear regression and the second data set was used to validate the results and compare to the prorated score method from the WAIS-IV manual. The prorated estimated scores correlated significantly with their counterparts and proved to be a better method of estimating the Full-Scale IQ and most of the index scores, but the regression equation was better at predicting the Processing Speed Index. The current study is consistent with the Ward (1990) and Pilgrim, Meyers, Bayless, & Whetstone (1999) studies and represents a reliable and valid way of assessing intellectual functioning in an abbreviated format.

Key words:

• intelligence tests
• neuropsychological tests
• psychological tests
• psychometrics
• Wechsler Adult Intelligence Scale

Notes

FSIQ = Full-Scale IQ; VCI = Verbal Comprehension; PRI = Perceptual Reasoning; WMI = Working Memory; PSI = Processing Speed.

*All p < .001.

Note. SEM from page 45, Table 4.3 of Wechsler et al. (2008) for FSIQ = 2.16, VCI = 2.85, PRI = 3.48, WMI = 3.67, PSI = 4.78. R_ = Estimate based on the regression equation; P_ = Estimate based on prorated score equation.

Note. Guidelines used in interpreting effect size: negligible ≤.19; small =.20 − .49; medium = .50–.79; large =.80 (Cohen, 1988). R_ = Estimate based on the regression equation; P_ = Estimated based on prorated score equation.

R_ = Estimate based on the regression equation; P_ = Estimated based on the prorated score.

R_ = Estimate based on the regression equation; P_ = Estimated based on the prorated score.

*Clinically inaccurate.