Norms, normality, and clinical significant change: Implications for the evaluation of treatment outcomes for eating disorders

Objective: The implications of the use of national norms of the Eating Diso rders Inventory (EDI) are investigated. Method: A German version of the EDI was administered to a representative national sample (n = 650), a repeated ly measured community sample (n = 207), and a national inpatient sample wit h primary diagnoses of anorexia or bulimia nervosa (n = 959). Resulting sca le distributions were compared with those of North American samples of the handbook. Results: Normal ranges on several scales markedly differed when G erman community norms were used. When estimates of rates of clinical signif icant changes were based on German norms instead of on North American norms , rates were markedly lower for scales measuring core diagnostic features ( e.g., binging/purging, Drive for Thinness) and higher for those measuring c orrelates (e.g., Maturity Fears, Interpersonal Distrust). Discussion: Negle cting differences in national norms can lead to substantial misinterpretati on of empirical findings in the diagnosis of eating disorders and the evalu ation of treatment outcome. (C) 2001 by John Wiley & Sons, Inc.