Assessing base rates of sexual behavior using the unmatched count technique

Estimating the prevalence of sexual behaviors is difficult because of self-report biases. This is particularly relevant in assessing high-risk sexual behaviors for the purpose of reducing the transmission and acquisition of sexually transmitted infections (STIs) and HIV/AIDS. The present study employed the unmatched count technique (UCT), which provides estimates of the prevalence of risky sexual behaviors without requiring participants to confess to socially undesirable or stigmatized behaviors. Compared to a standard, anonymous self-report questionnaire, the UCT protocol revealed that people were less likely to notify their partners about STIs or discuss their history of sexual experiences. Effects were particularly large in women suggesting that women may be more likely to misrepresent their sexual behaviors. The findings suggest that conventional, anonymous self-report questionnaire data of base rates of risky sexual behavior and sexual communication are consistently inaccurate. These discrepant base rates suggest that the UCT might provide a better estimate of the frequency of these behaviors. Results suggest that inconsistent sexual behavior is more rampant than anonymous questionnaires suggest. They also underscore the need for improvements in the anonymity of assessment of sexual behaviors, which could in turn improve the targeting of prevention efforts. Results have important public health implications because accurate assessment of sexual behaviors is crucial for developing effective STI prevention interventions among target populations.