Faculty Proceedings, Presentations, Speeches and Lectures

A National Survey of Symptom Exaggeration and Malingering Base Rates

Event Name/Location

30th Annual Meeting of the International Neuropsychological Society

Event Location / Date(s)

Toronto, Ontario, Canada / February 13-16, 2002

Presentation Date


Document Type

Conference Proceeding



National Survey of Symptom Exaggeration and Malingering Base Rates. The annual incidence or base rate of symptom exaggeration0malingering has been the subject of estimates that vary widely in magnitude and objectivity. Accurate base rate statistics are necessary for the calculation of diagnostic accuracy estimates. Base rates of exaggeration0malingering are reported from a survey of the ABCN membership. The response rate was 35% (N=131). Respondents’ geographic distribution matched that of the ABCN membership. Base rates of exaggeration0malingering did not differ among geographic regions or practice settings, but were related to the proportion of plaintiff vs. defense referrals (r = .22). Reported base rates would be 2% to 4% higher if variance due to referral source was controlled. The following estimates were based on 33,012 annual cases involved in personal injury (n = 6,272), disability (n = 3,631), criminal (n = 1,321), or medical (n = 21,788) matters: 29% of personal injury cases, 30% of disability claims, 19% of criminal cases, and 8% of medical cases involved probable symptom exaggeration0malingering; 39% of mild head injury, 35% of fibromyalgia0chronic fatigue, 31% of chronic pain,27% of neurotoxic disorder, and 22% of electrical injury claims involved exaggeration0malingering. Diagnostic impressions were supported by multiple sources of evidence, including severity (65% of cases) or pattern (64% of cases) of cognitive impairment that was inconsistent with the condition, scores below empirical cutoffs on forced choice tests (57% of cases), discrepancies among records, self-report, and observed behavior (56%), implausible self-reported symptoms in interview (46%), implausible changes in test scores across repeated examinations (45%), and validity scales on objective personality tests (38%).

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