Effect of perceived anonymity in assessments of eating disordered behaviors and attitudes

Objective: The present study assessed the effect of perceived anonymity on endorsements of eating disordered behaviors and attitudes across multiple response formats. Method: Four hundred sixty-nine undergraduate women responded using one of three questionnaire formats: a nominally anonymous true/false condition, an unmatched count condition, or a randomized-response condition. Both the unmatched count and randomized response conditions provided complete response anonymity. Results: Significantly different endorsement rates were found for the majority of items when comparing the standard and unmatched count conditions, whereas differences were found for fewer items when comparing the standard and randomized response conditions. Perceived anonymity significantly differed across conditions, with the highest and lowest perceptions of anonymity found for the unmatched count and standard conditions, respectively. Discussion: Perceived anonymity and response format affect endorsements of eating disordered behaviors and attitudes, highlighting the necessity of understanding factors that contribute to response bias.