A 4pL Item Response Theory examination of perceived stigma in the screening of eating disorders with the SCOFF

Abstract

Abstract We examined the psychometric properties of the SCOFF, a screening instrument for eating disorders, with consideration of the perceived stigma of items that can produce socially desirable responding. The results of the current study suggest evidence of the sufficient psychometric properties of the SCOFF in terms of confirmatory factor and item response theory analyses. However, two items of the SCOFF revealed that individuals who otherwise endorsed other items of the SCOFF were less likely to endorse the items of Fat and Food. It is hypothesized that this is the result of perceived stigma regarding those two items that prompts individuals to respond in a socially desirable way. A weighted scoring procedure was developed to counteract the performance of these two items, but the psychometric performance was only slightly better and there would be a clear tradeoff of specificity over sensitivity if utilized. Future research should consider other ways to counteract such perceived stigma.