What Makes a Respondent-Driven Sampling “Seed” Productive? Example of Finding At-Risk Massachusetts Men Who Have Sex with Men

Abstract

Several recent studies have sought to elaborate upon the applicability and validity of respondent-driven sampling (RDS) to find hard-to-reach samples in general and men who have sex with men (MSM) in particular. Few published studies have elucidated the characteristics associated with initial RDS participants ("seeds") who successfully recruited others into a study. A total of 74 original seeds were analyzed from four Massachusetts studies conducted between 2006 and 2008 that used RDS to reach high-risk MSM. Seeds were considered "generative" if they recruited two or more subsequent participants and "non-generative" if they recruited zero or one participant. Overall, 34% of seeds were generative. In separate multivariable logistic regression models controlling for age, race, health insurance, HIV status, and the study for which the seed was enrolled, unprotected anal sex in the past 12 months [adjusted odds ratio (AOR)=6.68; 95% confidence interval (95% CI)=1.27-35.12; p=0.03], cocaine use during sex at least monthly during the past 12 months (AOR=8.81; 95% CI=1.68-46.27; p=0.01), and meeting sex partners at social gatherings (AOR=7.42; 95% CI= 1.58-34.76; p=0.01) and public cruising areas (AOR=4.92; 95% CI=1.27-19.01; p= 0.02) were each significantly associated with increased odds of being a generative seed. These findings have methodological and practical implications for the recruitment of MSM via RDS. Finding ways to identify RDS seeds that are consistently generative may facilitate collecting a sample that is closer to reflecting the MSM who live in all of the communities in a given location or study sample.

Evaluation of Respondent-Driven Sampling in a Study of Urban Young Men Who Have Sex with Men

“…Only the hypotheses regarding network size and stigmatization were supported. Although prior studies of adult MSM suggest that estimated network size may not be a significant productivity factor in RDS-based sampling, 19 we did find evidence to suggest it is an important factor among YMSM. More specifically, we found that controlling for other factors, YMSM with larger estimated eligible network (i.e., ≥10 people) may be up to 60 % more likely to recruit at least one additional person.…”

“…In terms of age, the homophily indices were positive and relatively low for both 16-18-year-olds and 19-20-years-olds (i.e., homophily indices of 0.26 and 0.16, respectively); estimated network size was slightly larger for younger participants (mean=6.1 for those ages 16-18 versus 5.3 for those ages [19][20]. Population estimates mirror these statistics with adjustment down in the younger group and up in the older group to account for differences in homophily and network size (i.e., 42.4 % ages 16-18 in the sample versus 37 % in the population, 57.6 % ages 19-20 in the sample versus 63 % in the population, respectively).…”

“…Study enrollees were instructed to recruit up to three eligible peers (i.e., sexual minority young men ages [16][17][18][19][20]. While study "coupons" were distributed initially, due to lost coupons, among other coupon problems, 23 we modified the approach to include use of a participant-specific and unduplicated password system in which participants chose and then distributed passwords via text, email, or other means.…”

“…[14][15][16][17] Furthermore, RDS samples may overrepresent individuals of lower socioeconomic status (i.e., who may have more reason to participate due to the recruitment incentives), including individuals living with HIV or those with substance use problems. [18][19][20][21][22] In addition, because less community connectedness has been cited as a more recent problem in recruitment of MSM generally, 18 YMSM who are more connected to the "gay" community and/or have larger eligible network sizes may be more efficient recruiters, facilitating more efficient chain recruitment. Finally, connections to sexual partners via social venues versus virtual venues may also be related to recruitment efficiency.…”

“…Finally, connections to sexual partners via social venues versus virtual venues may also be related to recruitment efficiency. 19 The purpose of this analysis was to evaluate the performance of RDS sampling among young urban YMSM (e.g., recruitment speed, sample characteristics, recruitment patterns, and network chain development) and to identify factors associated with individual-level recruitment success to inform future use of RDS with this population. We hypothesize that demographic, social, behavioral, and network factors, including racial/ethnic minority status, homelessness (i.e., as an indicator of socioeconomic marginalization), HIV-positive status, substance use problems, gay community connectedness, and network size, would be positively related to recruitment productivity, while sexual minority stigmatization, environmental barriers (e.g., parental monitoring), and meeting sex partners on the internet (i.e., virtual venue) would be negatively related to recruitment productivity.…”