Prorating Wechsler Adult Intelligence Scale-III summary scores

The application of the nine-subtest prorated version of the Wechsler Adult Intelligence Scale-ill (WAIS-III) in estimating Verbal, Performance, and Fu ll-Scale IQ scores was evaluated in a sample of 278 mixed clinical patients from two Department of Veterans Affairs Medical Centers. The composite rel iabilities of the three prorated summary scores, which excluded Comprehensi on and Picture Arrangement, did not differ from reliabilities from the full WAIS-III. All three prorated IQ summary scores demonstrated good alternate forms reliability with the standard WAIS-III summary scores. Ver bal Perfo rmance discrepancy scores were accurate for 86% of the cases. The results o f this study appear to support the regular use of prorated WAIS-III summary scores in estimating full WAIS-III summary scores. The benefit of this sys tem is that by giving all of the subtests required for the index scores, no t only are the index scores derived, but a very close estimation of the sum mary scores are generated. (C) 2000 John Wiley & Sons, Inc. J Clin Psychol 56. 807-811, 2000.