Effect of response format on endorsement of eating disordered attitudes and behaviors

Objective: The present study was designed to compare response rates on a standard self‐report questionnaire that was nominally anonymous to an unmatched count questionnaire that allowed for true anonymity in responding. Method: Four hundred and fifty‐four college students were asked about several topics, including attitudes towards weight and shape, dieting, and eating disordered behavior using one of two response formats; either a standard questionnaire in true‐false format or an unmatched count questionnaire that did not require participants to directly answer sensitive questions. Results: Both males and females had significantly different rates of endorsement between the two methods of assessment on the majority of the eating‐related questions. Conclusion: Response format and degree of anonymity affect endorsement of eating‐related thoughts and behaviors. Understanding response bias is critical to determining accurate rates of eating disordered thoughts and behaviors. © 2006 by Wiley Periodicals, Inc. Int J Eat Disord 2006