At least for these inpatients, a much higher SIMS total cut score (> 44) is required to achieve a very high specificity.
In fact, content analyses via ratings by teams of doctoral level clinicians with more than 35 years of experience each in clinical psychology or psychiatry indicated that the SIMS scales contain no items with the reasonable capacity to differentiate legitimate patients from malingerers[5,6,7,8].
[11] Archival data suggested that more than 70% of legitimate claims such as those for payments for therapies are thus falsely rejected or unduly delayed (see Gutierrez et al., page 16)[12] with iatrogenic consequences for the patients.
In the analysis of variance (ANOVA), there was no statistically significant difference between the more severely injured patients (those with post-concussion and whiplash syndrome and pain related insomnia) and malingerers: these two groups may report similar number of symptoms on the SIMS.
It has been also shown that the Low Intelligence scale (LI) of the SIMS consists mainly of arithmetic and logical reasoning tasks or tasks assessing general knowledge on which patients tired by chronic illness, or those with the post-concussion syndrome, or persons whose attentional focus is disrupted by chronic pain may perform worse than uninjured persons[8,14].
As a consequence, none of the SIMS scales shows an adequate criterion validity when the data from patients injured severely in high impact car accidents was compared via ANOVA to data from less injured persons, from malingerers, and from uninjured non-malingering normal persons.
These authors[3] mentioned, with respect to SIMS cutoff of > 14 points, that “research (e.g., Clegg et al., 2009[16]) has found that non-feigning clients often exceed this cut score.” Rogers and his research team suggested that the cutoff for SIMS total score might need to be set as high as > 44 points to improve specificity, when dealing with certain diagnostic groups.
[3] Statistics provided by Rogers et al. suggested that more than two thirds of honestly responding psychiatric patients would be misclassified as malingerers.
The first was to locate SIMS items listing medical symptoms reported rarely by the honest group but frequently by the exaggerating group: "The rare symptoms (RS) scale was created by identifying SIMS items endorsed by less than 10% of genuine responders but more than 25% of feigners."
A third of the RS items are logical or algebraic reasoning tasks on which patients with severe post-concussive symptoms and fatigue from insomnia (such as caused by persistent pain) could perform less well.
[23] Patients with cerebral microvascular injuries and axonal shearing from their accident are more likely to score higher on the RS and be misclassified as “malingerers” than less injured persons.
Another third of RS scale items lists delusional symptoms or those of thought disorder: psychotic patients are more likely to be branded as “malingerers” and deprived of pharmacotherapy.
[23] Furthermore, Rogers's psychiatric sample on which the RS and SC scales were developed was diagnostically mixed, too heterogeneous, mainly diagnosed with PTSD (>77%) and/or mood disorders (>32%):[3] this makes generalizations of RS and SC cutoffs to other diagnostic groups of psychiatric patients uncertain.
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Cernovsky Z, Bureau Y, Mendonça J, Varadaraj Velamoor V, Mann S, Sidhu G, Diamond DM, Campbell R, Persad E, Oyewumi LK, and Woodbury-Fariña MA.
Validity of the SIMS Scales of Neurologic Impairment and Amnestic Disorder Archived 2020-06-14 at the Wayback Machine.
Cernovsky Z, Mendonça JD, Oyewumi LK, Ferrari JR, Sidhu G, and Campbell R. Content Validity of the Psychosis Subscale of the Structured Inventory of Malingered Symptomatology (SIMS).
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Cernovsky ZZ, Istasy PVF, Hernández-Aguilar ME, Mateos-Moreno A, Bureau Y, and Chiu S. Quantifying Post-Accident Neurological Symptoms Other than Concussion.
Cernovsky ZZ, Mendonça JD, Ferrari JR. Meta-Analysis of SIMS Scores of Survivors of Car Accidents and of Instructed Malingerers.
Cernovsky ZZ, Mendonça JD, Bureau YRJ, and Ferrari JR. Criterion Validity of Low Intelligence Scale of the SIMS Archived 2020-06-14 at the Wayback Machine.
Cima M, Hollnack S, Kremer K, Knauer E, Schellbach-Matties R, Klein B, Merckelbach H. „Strukturierter Fragebogen Simulierter Symptome“ Die deutsche Version des „Structured Inventory of Malingered Symptomatology: SIMS“.
Widows MR and Smith GP (adaptación: Héctor González Ordi y Pablo Santamaría).
Montrone A, Martino V, Grattagliano I, Massaro Y, Campobasso F, Lisi A, Di Conza A, Catanesi R. L'uso del test sims nella valutazione psicodiagnostica delle condotte distorsive: la simulazione.
Chapter 23 in Psicologia forense: Instrumentos de avaliação (editors Simões MR, Almeida LS, Gonçalves MM).
Cernovsky ZZ and Ferrari JR. Rogers’s RS und SC malingering scales derived from the SIMS.