Improving the clinical utility of the SIRS cognitive items: Preliminary reliability, validity, and normative data in pretrial and clinical samples

Abstract

The utility of the Structured Interview of Reported Symptoms [SIRS; Rogers, R., Bagby, R. M., & Dickens, S. E. (1992). Structured Interview of Reported Symptoms professional manual. Odessa, FL: Psychological Assessment Resources], Improbable Failure Rate (IF) scale in pretrial (N=64) and clinical (N=153) samples was explored. Internal consistencies of the IF items were alpha=.81 and alpha=.92, respectively, with split-half reliabilities of .89 and .84, respectively. The IF scale loaded distinctly from the SIRS primary (psychosis) scales in principal components analysis, and the pattern of performances among clinical groups were as expected (e.g., normal controls outperformed patients with focal lesions and dementia, CHI patients outperformed dementia patients). Performance on the IF items was correlated with MMSE score (r=-.59, p<or=.001), age (r=.53, p<or=.001), and education (r=.31, p<or=.001), but not with Barona estimated FSIQ (r=-.14, p=.08). For normals and psychiatric patients there was a clear falling off of IF error scores after 1 error, and for CHI patients the fall off began after 2 errors. Results lend credence to the SIRS IF scale as an acceptable screening measure for feigned cognitive abilities.

Use of the SIRS in compensation cases: An examination of its validity and generalizability.

“…Based on the floor-effect detection strategy, IF consists of 20 items requiring provision of antonyms (10) or rhymes to very simple words (10). Despite the organization into antonyms and rhymes, initial data suggest that these items may form a single dimension (Rogers, Jackson, Sewell, & Salekin, 2005;Wynkoop, Frederick, & Hoy, 2006) and be potentially effective for detecting cognitive feigning (Wynkoop et al, 2006). However, relatively little research has evaluated the effectiveness of the IF scale against established measures of FCI.…”

Evaluation of the Response Bias Scale and Improbable Failure Scale in assessing feigned cognitive impairment.

“…In fact, nonintellectually impaired individuals feigning deficits, and intellectually impaired individuals, performed similarly. For these reasons, in contrast to Wynkoop and colleagues’ (2006) recommendation, the researchers concluded that the IF scale should not be used as a screening measure of FCI. Rogers and colleagues (2009) advocated for the use of a revised version of the IF scale (i.e., IF-revised), that included only items with specificities over 90%, and used a cutoff score of zero to identify genuine participants.…”

An Investigation of the ECST-R in Male Pretrial Patients

“…These results cannot be conclusively interpreted as evidence of feigning but suggest patients classified as probable feigning on the SIRS are more likely to also feign cognitive impairment. To provide an additional test for this hypothesis, we evaluated the Improbable Failure (IF) rate scale (Rogers et al, 1992;Wynkoop, Frederick, & Hou, 2006), which consists of four groups of five items measuring an individual's ability to complete simple cognitive tasks. As noted by Wynkoop et al (2006), the IF scale relies on the floor effect detection strategy, with errors indicative of feigned cognitive impairment.…”

“…To provide an additional test for this hypothesis, we evaluated the Improbable Failure (IF) rate scale (Rogers et al, 1992;Wynkoop, Frederick, & Hou, 2006), which consists of four groups of five items measuring an individual's ability to complete simple cognitive tasks. As noted by Wynkoop et al (2006), the IF scale relies on the floor effect detection strategy, with errors indicative of feigned cognitive impairment. Notably, the items on the IF scale are not used to classify patients as honest responders or probable malingerers.…”