Estimates of Non-Heterosexual Prevalence: The Roles of Anonymity and Privacy in Survey Methodology.

When do people feel comfortable enough to provide honest answers to sensitive questions? Focusing specifically on sexual orientation prevalence-a measure that is sensitive to the pressures of heteronormativity-the present study was conducted to examine the variability in U.S. estimates of non-heterosexual identity prevalence and to determine how comfortable people are with answering questions about their sexual orientation when asked through commonly used survey modes. We found that estimates of non-heterosexual prevalence in the U.S. increased as the privacy and anonymity of the survey increased. Utilizing an online questionnaire, we rank-ordered 16 survey modes by asking people to rate their level of comfort with each mode in the context of being asked questions about their sexual orientation. A demographically diverse sample of 652 individuals in the U.S. rated each mode on a scale from -5 (very uncomfortable) to +5 (very comfortable). Modes included anonymous (name not required) and non-anonymous (name required) versions of questions, as well as self-administered and interviewer-administered versions. Subjects reported significantly higher mean comfort levels with anonymous modes than with non-anonymous modes and significantly higher mean comfort levels with self-administered modes than with interviewer-administered modes. Subjects reported the highest mean comfort level with anonymous online surveys and the lowest with non-anonymous personal interviews that included a video recording. Compared with the estimate produced by an online survey with a nationally representative sample, surveys utilizing more intrusive methodologies may have underestimated non-heterosexual prevalence in the U.S. by between 50 and 414%. Implications for public policy are discussed.