Six commonly used instruments for assessment of eating disorders were analyzed. Effect size results from Erford et al.'s (2013) meta-analysis for the treatment of bulimia nervosa were used to compare each scale's ability to measure treatment outcomes for bulimia nervosa. Effect size comparisons indicated higher overall effect sizes using the Eating Disorder Inventory and Eating Attitudes Test in assessing bulimia and the Eating Disorder Examination and the Body Shape Questionnaire in assessing body dissatisfaction. (Contains 2 tables.)