JMIR Publications

ABSTRACT

Background:

Obtaining a representative sample is a substantial challenge when undertaking health research among hidden and hard-to-reach populations such as men who have sex with men (MSM). Web-based Respondent Driven Sampling (WEB RDS) was developed to overcome such sampling challenges and to create population estimates based on network and sampling characteristics. Despite a decade of research, it remains unclear whether WEB RDS is suitable for sampling hidden populations such as MSM.

Objective:

This study’s objective is to evaluate how viable WEB RDS methodology is for obtaining a nationwide sample of MSM, suitable for population inference of sexual health characteristics, in Belgium.

Methods:

We adapted the Medical Resource Council (MRC) process evaluation framework for interventions, to evaluate an empirical WEB RDS. Viewing ‘WEB RDS’ as a complex intervention with respondent-driven recruitment as the aim, we evaluated indicators of context, implementation, mechanisms of impact, and performance. We analysed the data using a mixed-methods approach that integrated findings from quantitative analysis, such as RDS diagnostics, and qualitative thematic analysis.

Results:

Sampling did not reach a sufficient sample size (n=193) to compensate for a RDS design effect of 3 and the number of recruitment waves was low (waves=7). A visual examination of the convergence and bottleneck plots indicate that many more waves of recruitment would be needed for population estimates to become independent of the seeds. However, producing further waves was impeded by challenges inherent to the research context and process. MSM and MSM community organization representatives indicated that, in Belgium, MSM are over-researched, with low motivation for the topic of sexual health and digital etiquette dictating not sharing survey links. A moderate reward of EUR 10–30 with a dual incentive structure was insufficient to overcome these barriers.

Conclusions:

This study indicates that WEB RDS, even with a moderate incentive, is not a viable sampling strategy for obtaining population estimates of sexual health traits of MSM in Belgium. The study emphasizes the need for understanding MSM research motivation and topic saliency. Additionally, the study highlights the importance of online etiquette. Finally, the study showcases the utility of the adapted MRC framework for evaluating WEB RDS methodology.