Evaluating sampling biases from third-party reporting as a method for improving survey measures of sensitive behaviors

Survey participants often misreport their sensitive behaviors (e.g., smoking, drinking, having sex) during interviews. Several studies have suggested that asking respondents to report the sensitive behaviors of their friends or confidants, rather than their own, might help address this problem. This is so because the "third-party reporting" (TPR) approach creates a surrogate sample of alters that may be less subject to social desirability biases. However, estimates of the prevalence of sensitive behaviors based on TPR assume that the surrogate sample of friends is representative of the population of interest. We used sociometric data on social networks in Likoma, Malawi to examine this assumption. Specifically, we use friendship network data to investigate whether friends have similar socio-economic characteristics as index respondents, and to measure possible correlations between the likelihood of inclusion in the surrogate sample and sensitive behaviors. From these results, we suggest approaches to strengthen estimates of the prevalence of sensitive behaviors obtained from TPR.