Selecting Tetradic Short Forms of the Taiwan Wechsler Adult Intelligence Scale IV

Factor-based Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) tetrads were investigated using the Taiwan WAIS-IV standardization sample of 1,105 normal adults aged between 16 and 90 years. Various psychometric characteristics, time constraints, and qualities of estimation were compared among 90 tetrads using linear equation procedures. Among the tetrads, the Information-Visual Puzzle-Digit Span-Digit Symbol combination had higher performance than the other combinations with respect to overall estimation quality and time saved. Moreover, the Similarities-Visual Puzzle-Digit Span-Digit Symbol, Information-Matrix Reasoning-Digit Span-Digit Symbol, and Information-Visual Puzzle-Letter Number Sequencing-Digit Symbol combinations obtained the most efficient estimates. For clinicians who value the utility of Block Design, the Information-Block Design-Digit Span-Digit Symbol combination was found to provide high estimation quality. The findings also revealed that the previously recommended Wechsler Adult Intelligence Scale-Third Edition tetrads are no longer the best solutions for the WAIS-IV. Furthermore, even the selected WAIS-IV tetrads had substantial misclassification rates; the four-factor short forms tend to underestimate the full-scaled IQ for highly intelligent adults. Therefore, these short forms should be used cautiously and for screening purposes only.