Design and implementation of a web-based, respondent-driven sampling solution

Background: Respondent-driven sampling (RDS) refers both to a chain-referral sampling method and an analytical model for analysing sampled data. Web-based respondent-driven sampling (webRDS) uses internet-based recruitment coupled with an electronic survey to carry out RDS studies. There is currently no commercially available webRDS solution. We designed and developed a webRDS solution to support a research study aimed at estimating mortality in Yemen. We report here on the design of the webRDS solution and its implementation. We developed a webRDS solution comprised of an existing survey platform (i.e. ODK) and a bespoke RDS system. The RDS system was designed to administer and manage the survey cascade and included: 1) an application programming interface, 2) a study participant client, and 3) an administrator interface. Results: : We consulted members of the Yemeni diaspora throughout the development of the solution. Technical obstacles were largely the result of WhatsApp’s policies on bulk messaging and automated messaging behaviour, the inherent constraints of SMS messaging and SMS filtering behaviour. Language support was straight-forward yet time consuming. Survey uptake was lower than expected. Factors which may have impacted uptake include: our use of consumable survey links, low interest amongst the diaspora population, lack of material incentives, and the length and subject matter of the survey itself. The SMS/WhatsApp messaging integration was relatively complex and limited the information we could send potential participants. Conclusion: Despite lower-than expected survey uptake we believe our webRDS solution provides efficient and flexible means to survey a globally diverse population.