WAIS-R item difficulties with psychiatric inpatients.

Item difficulties for 10 WAIS-R subtests were determined for a sample of psychiatric inpatients (N = 150). Spearman correlation coefficients between psychiatric inpatient and standardization group rank orders were large and significant across all subtests except Object Assembly, which demonstrates the expected trend of increasing item difficulty for the psychiatric inpatient sample. Using linear regression, items with standardized residuals greater than two were judged to be significantly out of order for the psychiatric inpatient sample. Of the 165 WAIS-R items examined in this study, only 7 were found to be out of order. This result may have been due to chance and suggests that, in general, WAIS-R subtest item difficulty curves for psychiatric inpatients and the WAIS-R standardization group are comparable.