For my research question, I propose an RCT to assess the effects of a behavioral counseling intervention on reducing the risk of opioid overdose among individuals who inject drugs.
People who inject drugs (PWIDs) can be a difficult population to reach because many PWIDs live in fringe locations, do not access health services and may have a general distrust of government systems. Probabilistic sampling therefore is not an ideal approach to reach this high-risk yet hard-to-reach population.
To enroll PWIDs in this study, I would use respondent driven sampling because it will allow me a greater chance of reaching otherwise hard to reach individuals through their own social networks. We would enroll individual seeds who have large social networks (family, friends etc). We would recruit seeds through convenience sampling at the local syringe exchanges and/or through snowball sampling from other participants/seeds. The seeds would then reach their own networks to encourage individuals to participate in the study.
The advantages of this method is that it would allow us to reach some of the most difficult-to-reach PWIDs who may not have otherwise accessed the study. However, RDS also has its challenges. First, it may introduce selection bias – as seeds and their recruited participants may be similar to one another yet not representative of the larger PWID population. We would try to capture a diverse group of initial seeds (geography, race/ethnicity/gender/age/drug of choice etc.) to try to mitigate the problem. For instance, we would ensure that at least one seed would come from the Bayview/Hunters Point area as that is a location geographically isolated from most PWID services centered in the TL and Soma. However even with directly seed identification selection bias certainly remains a concern.The second problem is that RDS can be very difficult to implement. RDS means you have to rely on the seeds for recruitment which may be challenging if seeds are not recruiting as quickly or as many individuals as they said they would. There is less control over the recruitment process than when a study’s own recruitment team does the recruiting directly.