Inability of the Rarely Missed Index to identify simulated malingering under more realistic assessment conditions

Abstract

The Wechsler Memory Scale-III (WMS-III) Rarely Missed Index (RMI) was developed by Killgore and DellaPietra (1999b, 2000b, 2001) to detect malingering. Its development was based on item-response biases in the Logical Memory Delayed Recognition (LMDR) items of the WMS-III (Killgore & DellaPietra, 1999a, 2000a). We completed replication studies using undergraduates, analog malingerers, and patients. In Experiment 1, 100 undergraduates naïve to the WMS-III Logical Memory stories were administered the LMDR, and item-response biases were explored. In Experiment 2, 49 undergraduates feigned brain injury on cognitive and symptom validity tests. Data were also extracted from 83 traumatic brain injury (TBI), dementia, psychiatric/pain, stroke, and other patient files. Neither the previously reported item-response biases nor the diagnostic utility of the RMI in identifying simulated malingerers were replicated.

Kristen M. Harris is now a graduate student at the Department of Psychology, Nova Southeastern University. Financial support for this research was provided to the first author by the Office of the Dean of the College of Arts and Behavioral Sciences, Saginaw Valley State University, and to the second author by the Saginaw Valley State University Faculty Association's Endowed Scholarship program. Completion of this work was made possible by sabbatical leave granted the first author. We gratefully acknowledge the support. Parts of this paper were presented at the American Psychological Association's 111th Annual Convention in Toronto, 9 August 2003.