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Normal Wechsler Adult Intelligence Scale (WAIS)-IV performance relative to average normative scores alone can be an oversimplification as this fails to recognize disparate subtest heterogeneity that occurs with increasing age. The purpose of the present study is to characterize the patterns of raw score change and associated variability on WAIS-IV subtests across age groupings. Raw WAIS-IV subtest means and standard deviations for each age group were tabulated from the WAIS-IV normative manual along with the coefficient of variation (CV), a measure of score dispersion calculated by dividing the standard deviation by the mean and multiplying by 100. The CV further informs the magnitude of variability represented by each standard deviation. Raw mean scores predictably decreased across age groups. Increased variability was noted in Perceptual Reasoning and Processing Speed Index subtests, as Block Design, Matrix Reasoning, Picture Completion, Symbol Search, and Coding had CV percentage increases ranging from 56% to 98%. In contrast, Working Memory and Verbal Comprehension subtests were more homogeneous with Digit Span, Comprehension, Information, and Similarities percentage of the mean increases ranging from 32% to 43%. Little change in the CV was noted on Cancellation, Arithmetic, Letter/Number Sequencing, Figure Weights, Visual Puzzles, and Vocabulary subtests (<14%). A thorough understanding of age-related subtest variability will help to identify test limitations as well as further our understanding of cognitive domains which remain relatively steady versus those which steadily decline.

The Structured Inventory of Malingered Symptomatology (SIMS) is a 75-item, self-report measure to be used with individuals at least 18 years of age, which may be utilized to assess potential malingering of psychosis, neurologic impairment, amnesia, low intelligence, or affective disorder. However, no studies in the literature have examined the diagnostic validity of this instrument in a known-groups design involving medicolegal referrals diagnosed as malingering using the criteria outlined by Slick and colleagues [Slick, D. J., Sherman, E. M. S., & Iverson, G. L. (1999). Diagnostic criteria for malingered neurocognitive dysfunction: Proposed standards for clinical practice and research. The Clinical Neuropsychologist, 13, 545-561]. The current known-groups, archival study was designed to examine the effectiveness of the SIMS at identifying malingering in patients involved in personal injury lawsuits or disability claims. Findings indicate that a higher cut score on the SIMS for identification of malingering may be appropriate for use with this population. Limitations, clinical implications, and suggestions for further research are discussed.

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