Utility of WAIS-R short forms in schizophrenia

Recently, short forms of the Wechsler Adult Intelligence Scale-Revised (Wechsler, 1981) have received increasing attention because of their ability to provide estimated IQ scores with substantial time savings (in some cases 85-90% savings). These short forms may have particular utility for individuals with schizophrenia because they require less time to administer and, as a result, are less taxing for these patients who often exhibit impaired attention and deficient motivation. In this study, we examine the psychometric properties of nine popular WAIS-R short forms in a group of 143 patients diagnosed with schizophrenia. Our results indicated that Kaufman's four subtest short form was the best overall estimator of Full Scale IQ (FSIQ) when a combination of administration time and psychometric properties were considered. However, Ward's seven subtest short form provided the closest estimation of FSIQ and had the lowest misclassification rate, while also providing estimates of Verbal and Performance IQs and yielding 46.5-49.7% time savings. All short forms had substantial misclassification rates, indicating that caution is warranted when using these forms to classify individuals according to standard levels of intellectual functioning (e.g., Average, Low Average, High Average). Clearly, the main consideration in selecting a short form is whether time savings or accuracy have priority.