Department of Applied Health Sciences, Indiana University School of Public Health, Bloomington, Indiana, United States of America.
Department of International Health, Johns Hopkins University, Bloomberg School of Public Health, Baltimore, Maryland, United States of America.
PLoS One. 2020 Apr 10;15(4):e0231248. doi: 10.1371/journal.pone.0231248. eCollection 2020.
Respondent-driven sampling (RDS) is a peer-referral sampling methodology used to estimate characteristics of underserved groups that cannot be randomly sampled. RDS has been implemented in several settings to identify hidden populations at risk for HIV, but few studies have reported the methodological lessons learned on RDS design and implementation for assessing sexual risk behaviors in marginalized youth.
We used RDS to recruit N = 350 young adults, aged 18 to 22, who were living in urban slum settlements in Nairobi, Kenya. A structured survey was used to assess sexual risk behaviors. Twenty seeds were selected and asked to recruit up to three eligible peers. We used small monetary incentives and a three-day recruitment coupon with sequential numbers linking recruiters to their recruits.
Data collection was completed in 8 days with a maximum chain length of 6 waves. Each seed yielded 16 to 21 eligible recruits. Three (15%) seeds were unproductive and were replaced. RDS benefits were high identification rates (90% coupons returned per coupons given), high eligibility rates (100% eligible recruits per coupons returned), and high efficiency (~39 eligible recruits per day). 44% of the sample was female. Most recruits (74%) reported being "friends" for 7+ years with their recruiter. RDS overcame feasibility concerns of household-, clinic-, and school-based sampling methodologies in that underserved youth who were unemployed (68%), out of school (48%), ethnic minorities (26%), and having prior residential instability (≥2 moves in the past year) (20%) were successfully recruited, based on weighted analyses. Youth reporting HIV risk behaviors, including unprotected sex (38%), sex while high/drunk (35%), and sex exchange for pay (14%), were also enrolled. However, 28% were not sexually active within the last 6 months. Challenges included managing wait times during peaks and participant referral expectations. Community engagement, use of study-stamped coupons, broad inclusion criteria, incentives, and study sites within walking distances all contributed to the successful implementation of the sampling methodology.
RDS is an important tool in reaching a diverse sample of underserved and at-risk young adults for study participation. Implications for optimizing RDS for behavioral studies in this population are discussed.
回应驱动抽样（RDS）是一种同伴推荐抽样方法，用于估计无法随机抽样的服务不足群体的特征。RDS 已在多个环境中实施，以识别处于 HIV 风险中的隐藏人群，但很少有研究报告在设计和实施 RDS 以评估边缘化青年的性风险行为方面所获得的方法学经验。
我们使用 RDS 招募了 350 名年龄在 18 至 22 岁之间的年轻人，他们居住在内罗毕的城市贫民窟。使用结构化调查评估性风险行为。选择了 20 个种子并要求他们招募最多 3 名符合条件的同伴。我们使用小额经济激励措施和带有连续编号的三天招募优惠券，将招募者与他们的招募对象联系起来。
数据收集在 8 天内完成，最大链长为 6 波。每个种子产生 16 至 21 名符合条件的招募对象。有 3 个（15%）种子没有产生效果，因此被替换。RDS 的好处是高识别率（每个发放的优惠券返回 90%）、高资格率（每个返回的优惠券都有 100%的合格招募对象）和高效率（每天约有 39 名合格招募对象）。样本中 44%为女性。大多数招募对象（74%）与招募者“朋友”关系超过 7 年。RDS 克服了基于家庭、诊所和学校的抽样方法的可行性问题，因为失业（68%）、失学（48%）、少数民族（26%）和过去一年内居住不稳定（≥2 次搬迁）（20%）的服务不足青年也成功招募，这是基于加权分析的结果。报告 HIV 风险行为的青年，包括无保护性行为（38%）、性行为时醉酒/兴奋（35%）和性交换报酬（14%），也被招募。然而，28%的人在过去 6 个月内没有性行为。挑战包括在高峰期管理等待时间和参与者推荐期望。社区参与、使用加盖研究印章的优惠券、广泛的纳入标准、激励措施以及距离研究场所步行可达的位置，都有助于成功实施抽样方法。
RDS 是一种重要的工具，可以帮助研究人员接触到多样化的服务不足和处于风险中的年轻成年人，以参与研究。讨论了针对这一人群优化 RDS 用于行为研究的意义。
