List randomization for prevalence estimation of sensitive behavioral data among women with HIV of reproductive age in Lilongwe, Malawi

Self-reported data is subject to reporting biases including social desirability bias. List randomization is one method that can help mitigate the impact of such biases. Here, we examined the utility of list randomization among women living with HIV of reproductive age in sub-Saharan Africa. In the Family Planning and Antiretroviral Therapy study, participants were randomized to answer five blocks of true/false statements via either direct or list response. Each block contained three non-sensitive statements and one sensitive statement related to either condom use or HIV disclosure. For each sensitive statement, we calculated the prevalence difference (PD) comparing list response to direct response overall and stratified by socioeconomic status. The PD for four of the sensitive statements was negligible. However, we found that self-report of always using a condom was reported by 53.1% at list response visits versus 34.7% at direct response visits (PD: 18.5%; 95% CI: 6.2%, 30.7%), a difference that was attenuated among those with higher socioeconomic status. In this setting, list randomization did not meaningfully change the estimated prevalences for most questions, except for one question which unexpectedly produced a higher estimate for a positive behavior. Examining this method in other settings and populations is warranted.