Validation of a screening instrument for identifying risk behaviour related to eating disorders

Abstract

AbstractObjective:To validate a screening instrument (RiBED‐8) aimed at identifying risk behaviour related to eating disorders among Danish adolescents in a two‐stage study in 1996 and a follow‐up study 2.75 years later.Methods:2094 pupils, aged 14–21 years, responded to a 49‐item self‐report questionnaire. Risk behaviour related to eating disorders was defined. The psychometric validation procedure was performed with Rasch Item analysis, testing the internal and external homogeneity, local independence and uni‐dimensionality. Furthermore, 91 semi‐structured clinical interviews were conducted to create a gold standard and to test the content, criterion and construct related validity of risk behaviour. Eight items comprised the final scale, called RiBED‐8. Furthermore, the criterion‐related validity, the stability and the predictive validity of RiBED‐8 was tested using the Eating Disorders Inventory (EDI‐2) in the follow‐up study in 1998, where 508 pupils responded. In a cross‐sectional design in 1998, the concurrent general psychopathology was analysed using Hopkins Symptoms CheckList (SCL‐90‐R). Lastly, the time‐related reliability of the instrument was tested by test–retest analysis in 1998.Results:The scale was a uni‐dimensional screening instrument with local independence, internal consistency and external homogeneity towards age groups. However, the instrument did not measure less severe risk behaviour for boys. RiBED‐8 had sufficiently good psychometric properties (construct, criterion and predictive validity and test–retest reliability), and identified persons with a high level of general psychological distress and of eating pathology. Risk behaviour related to eating disorders was stable and indicated a 5.6‐times greater relative risk of having eating disorders over 2.75 years. Copyright © 2003 John Wiley & Sons, Ltd and Eating Disorders Association.