Assessment of malingering with simulation designs: Threats to external validity.

Abstract

Comprehensive forensic evaluations are predicated on the accurate appraisal of response styles that may affect evaluatees' clinical presentation and experts' conclusions associated with psycholegal isslIes. In the assessment of malingering, forensic experts often rely heavily on standardized measures that have been validated exclusively via analogue research. While sllch research augments intemal validity, the threats to external validity are readi(v apparent. As the first study of these threats, type of incel/tive (positive verslIs negative), context (a familiar versus IInfamiliar scenario), and relevance to the participants was investigated ~}'stematically with a between-subjects factorial design. A sample of 231 undergraduates was asked 10 either (a) feign major depression and given on easily understood description of this disorder or (b) serve as controls responding .lOnestly. They were administered a brief measure of psychopathology (Hopkins Symptom Checklist; Derogatis, Lipmall, Rickels, Uhlenhuth, & Cov;, 1974) and a recent screen for malingering (Screening InventOlY of Malingered Symptoms or SIMS; Smith, 1992) in 1 of 18 experimental conditions. Results suggested that incentive had a main effect on the SIMS. MOle ~pecifically, simulators Ilnder negative incentives appeared more focused in their feigning; they produced more bogus depressed symptoms, bill fewer symptoms unrelated /0 depression. Interactions were also observed between context and incentive, and context and relevance. Implications of these results are explored for both analogue research on malingering and current forensic practice.A cornerstone of forensic evaluations is the effective evaluation of malingering and related response styles. Given the adversarial nature of most forensic assessments, psychologists and other mcntal health profes.~ionals must address the potential for malingering for nearly all psycholegal issues (Rogers & Mitchell, 1991). Recent survey data (Rogers, Salek in, Sewell, & Goldstein, 1996; Rogers, Sewell, & Goldstein, in press) suggest that the prevalence of malingering varies widely across forensic settings, but is likely to compose approximately one sixth of all forensic cases. With malingering as both a critical and common issue in forensic assessments, the empirical bases of these determinations are crucial.

Diagnostic accuracy of the Structured Inventory of Malingered Symptomatology (SIMS) in detecting instructed malingering

“…Firstly, in our simulation conditions, malingerers did not receive positive or negative incentives. Meanwhile, there are good reasons to believe that such incentives might affect SIMS scores (Rogers & Cruise, 1998). Secondly, our patient sample was small and diagnostically heterogeneous.…”

Detection of malingered attention deficit hyperactivity disorder

“…Whether the results of the present study can be generalized to other populations (e.g., non-student malingering and patient groups) is questionable. In general, the main methodological problem associated with studies using simulation designs refers to the external validity of the results (Rogers 1997;Rogers and Cruise 1998). …”

Investigating the M‐FAST: psychometric properties and utility to detect diagnostic specific malingering

“…Efforts were made to create a scenario with appropriate context, relevance and incentive to attenuate threats to external validity (Rogers & Cruise, 1998). Simulators were provided with one of four sets of written instructions that corresponded to the experimental diagnostic condition to which they were assigned.…”