Social network-based methods are increasingly used to estimate induced abortion incidence and investigate correlates. Approaches differ in the social tie definitions used to identify which social network members' abortion experiences respondents will report. This study compares the effect of using the "best friend" (closest female friend) versus "confidante" (specifying mutual sharing of personal information) definition on abortion incidence estimation. We use data from a nationally representative survey of women aged 15-49 in Burkina Faso (conducted in 2020-2021) where respondents were randomized into two versions of an abortion module, using different friend definitions. We computed abortion rate estimates by friend definition and adjusted for assumption violations (transmission bias, surrogate sample selection bias). Unadjusted incidence rates varied from 11.7 [4.1-19.2] abortions per 1,000 women to 15.6 [9.7-21.4], depending on friend definition. The confidante definition yielded higher adjusted estimates (36.2 [25.1-47.2]) than the best friend definition (17.0 [8.7-25.3]) due to greater transmission bias adjustment. Both estimates exceeded the respondent self-reported abortion incidence (4.0 [2.2-5.9]). Our results indicate that either friend definition produces higher incidence estimates than self-report but suggest a potential advantage for the "best friend" over the "confidante" definition given lower transmission bias. Further research should assess generalizability of these findings in other contexts.
© 2022 The Authors. Studies in Family Planning published by Wiley Periodicals LLC on behalf of Population Council.