Andy
Retired committee member
Paywall, https://academic.oup.com/acn/article-abstract/doi/10.1093/arclin/acaa017/5822934Objective
Base rates of invalidity in forensic neuropsychological contexts are well explored and believed to approximate 40%, whereas base rates of invalidity across clinical non-forensic contexts are relatively less known.
Methods
Adult-focused neuropsychologists (n = 178) were surveyed regarding base rates of invalidity across various clinical non-forensic contexts and practice settings. Median values were calculated and compared across contexts and settings.
Results
The median estimated base rate of invalidity across clinical non-forensic evaluations was 15%. When examining specific clinical contexts and settings, base rate estimates varied from 5% to 50%. Patients with medically unexplained symptoms (50%), external incentives (25%–40%), and oppositional attitudes toward testing (37.5%) were reported to have the highest base rates of invalidity. Patients with psychiatric illness, patients evaluated for attention deficit hyperactivity disorder, and patients with a history of mild traumatic brain injury were also reported to invalidate testing at relatively high base rates (approximately 20%). Conversely, patients presenting for dementia evaluation and patients with none of the previously mentioned histories and for whom invalid testing was unanticipated were estimated to produce invalid testing in only 5% of cases. Regarding practice setting, Veterans Affairs providers reported base rates of invalidity to be nearly twice that of any other clinical settings.
Conclusions
Non-forensic clinical patients presenting with medically unexplained symptoms, external incentives, or oppositional attitudes are reported to invalidate testing at base rates similar to that of forensic examinees. The impact of context-specific base rates on the clinical evaluation of invalidity is discussed.
Sci hub, https://sci-hub.tw/10.1093/arclin/acaa017
Base rates of invalidity have been well explored in forensic neuropsychological settings over the past two decades. Mittenberg, Patton, et al., (2002) initially surveyed board-certified neuropsychologists conducting forensic work. From their study, it was found that estimated base rates of malingering and symptom exaggeration were roughly 30% for examinees pursuing personal injury, disability, or workers’ compensation claims and roughly 20% for examinees with criminal charges. Additionally, neuropsychologists estimated that greater than 30% of forensic examinees with mild head injuries, fibromyalgia/chronic fatigue, or chronic pain met the criteria for probable malingering. Larrabee (2003) examined the empirical literature by reviewing 11 studies containing 1,363 consecutively evaluated litigants with mild traumatic brain injuries, finding that 40% of the examinees failed validity testing. Larrabee, et al., (2009) reviewed additional base rate data and found that rates of invalidity in settings where external incentives are present typically ranged between 30% and 50%, leading to the conclusion that the data “are sufficiently consistent to propose a new ‘magical number’ in neuropsychology: 40 ± 10” (p. 843)