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The criterion validity of the new subtests from the Wechsler Adult Intelligence Scale–Third Edition (WAIS–III; Wechsler, 1997) was evaluated in a sample of 100 patients with traumatic brain injury (TBI). Letter–Number Sequencing and Symbol Search, but not Matrix Reasoning, yielded statistically significant differences in performance between patients with moderate–severe TBI, patients with mild TBI, and demographically matched controls. Level of education accounted for a statistically significant amount of variance in the performance of patients with TBI, in addition to that explained by injury severity variables. It is concluded that Letter–Number Sequencing and Symbol Search have satisfactory criterion validity, but that they need to be supplemented with other measures in the context of neuropsychological evaluations. Matrix Reasoning, on the other hand, is not sensitive to the sequelae of TBI and more studies are needed to determine how it can be used for neuropsychological assessment purposes. (JINS, 2001, 7, 892–898.)

Since memory performance expectations may be IQ-based, unidirectional base rate data for IQ-Memory Score discrepancies are provided in the WAIS–III/WMS–III Technical Manual. The utility of these data partially rests on the assumption that discrepancy base rates do not vary across ability levels. FSIQ stratified base rate data generated from the standardization sample, however, demonstrate substantial variability across the IQ spectrum. A superiority of memory score over FSIQ is typical at lower IQ levels, whereas the converse is true at higher IQ levels. These data indicate that the use of IQ–memory score unstratified “simple difference” tables could lead to erroneous conclusions for clients with low or high IQ. IQ stratified standardization base rate data are provided as a complement to the “predicted difference” method detailed in the Technical Manual. (JINS, 2001, 7, 875–880.)

Reliability estimates for psychological tests are almost always reported for nonclinical populations (e.g., the normative samples). Such practice will no longer be sufficient as the new standards for testing call for an adequate assessment of psychometric properties within the specific population being tested. The purpose of this study was to provide internal consistency reliability estimates for clinical groups on the Wechsler Adult Intelligence Scale–Third Edition. The study included data from 403 clinical participants composed of 10 groups of adults recruited as part of the WAIS–III clinical validity studies. Split-half reliability coefficients were obtained for these groups replicating the procedure used in the WAIS–III. With 8 of the clinical groups, the split-half reliability coefficients were comparable to, or even higher than, those reported for the WAIS–III standardization sample. In general, the split-half coefficients for the Verbal subtests tended to be higher than the coefficients for the Performance subtests. The high magnitude and general pattern of these coefficients demonstrate that the WAIS–III scales do not include additional error variance above and beyond what is reported in the WAIS–III–WMS–III Technical Manual when it was used to assess certain clinical groups. For the ADHD/ADD and learning disabilities groups, however, the internal consistencies coefficients of some subtests were relatively lower, although not statistically significant, than the normative sample. These findings may reflect more heterogeneity within the groups. The implications for assessment and for using alternate methods of determining the psychometric properties in these populations are discussed. (JINS, 2001, 7, 862–866.)

While some of the modifications made to produce the WAIS–III and WMS–III (Wechsler, 1997a, 1997b) make sense from a neuropsychological standpoint, there are many questions still unanswered about the validity and reliability of these tests and their ultimate utility to neuropsychologists. The new tests have been criticized for having long administration times, which is problematic given pressures to decrease rather than increase the length and cost of neuropsychological evaluations (Ryan et al., 1998). Clinical neuropsychologists want to know if these tests can help them evaluate their patients more accurately with greater sensitivity and specificity than the alternatives, and experimental neuropsychologists want to know if they can help answer theoretical questions.