Concurrent validity of the Wechsler Abbreviated Scale of Intelligence and the Kaufman Brief Intelligence Test among psychiatric inpatients

This study examined the convergent and discriminant validity of the Wechsler Abbreviated Scale of Intelligence and the Kaufman Brief Intelligence Test for 85 psychiatric inpatients. The correlation between the WASI Full Scale and K-BIT Composite IQ scores was significant (r=.89, p<.001). Multitrait-multimethod analysis of the subtest scores showed that the K-BIT had higher internal consistency for its two subtests but, therefore, less differentiation of cognitive functioning than the brief Wechsler scale, as would be expected due to the larger number and diversity of the latter subtests. Correlations among the Wechsler scale subtests were lower than among those for the K BIT, so the former may tap different cognitive functions and yield more clinically useful information than the latter. This brief Wechsler scale appears to be a valid screening measure of verbal, performance, and general intellectual ability for use with an inpatient psychiatric Population when considerations of the setting or patient preclude administration of a longer measure of intellectual ability.