1 / 42

Lisa g. Johnston WWW.lisagjohnston, lsjohnston.global@gmail.Com

Sampling Adolescents/Young Key Populations (A/YKP) at Risk of HIV Exposure Using Respondent Driven Sampling (RDS). Lisa g. Johnston WWW.lisagjohnston.com, lsjohnston.global@gmail.Com University of California, san Francisco Tulane university, new Orleans. Outline.

celine
Télécharger la présentation

Lisa g. Johnston WWW.lisagjohnston, lsjohnston.global@gmail.Com

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Sampling Adolescents/Young Key Populations (A/YKP) at Risk of HIV Exposure Using Respondent Driven Sampling (RDS) Lisa g. Johnston WWW.lisagjohnston.com, lsjohnston.global@gmail.Com University of California, san Francisco Tulane university, new Orleans

  2. Outline • Why is RDS superior for sampling A/YKP? • RDS Overview • RDS Challenges • RDS Resources

  3. Why is RDS superior for sampling A/YKP? • Useful for gathering large samples of quantitative data from hard-to-reach and hidden populations • No sampling frame • Allows participants to remain anonymous • Peers recruit their peers (stigma, discrimination and lack of trust) • Has already been used successfully used in several countries to sample A/YKP • When analyzed correctly, provides representative findings about the network of the population sampled • Manuals and tools available to help you • Free computer software available Malekinejad M, et al. Using respondent-driven sampling methodology for HIV biological and behavioral surveillance in international settings: A systematic review. AIDS and Behavior. 2008.12(Suppl 1): 105-130. Johnston LG, Malekinejad M, Rifkin MR, et al. Implementation challenges to using respondent-driven sampling methodology for HIV biological and behavioral surveillance: Field experiences in international settings. AIDS and Behavior. 2008.12(Suppl 1): 131-141.

  4. RDS OVERVIEW • Basics and Challenges

  5. Questions to ask yourself before initiating RDS • Is the population of interest socially networked (i.e., they know each other as part of that population)? • Can you find a small number of persons who are part of the population?

  6. RDS Recruitment Chain

  7. RDS Recruitment Chain

  8. RDS Recruitment Chain

  9. RDS Recruitment Chain

  10. RDS Recruitment Chain

  11. RDS Recruitment Chain

  12. RDS Recruitment Chain

  13. RDS Recruitment Chain

  14. RDS Recruitment Chain

  15. RDS Recruitment Chain

  16. RDS Recruitment Chain

  17. RDS Recruitment Chain

  18. RDS Recruitment Chain

  19. RDS Recruitment Chain

  20. RDS Basics • Is both a sampling and analysis method • A big challenge for those developing RDS is to match the estimators to the sampling design assumptions • Type of chain referral sampling method to reach hidden populations • Begin with a set of ‘seeds’ • Seeds recruit peers, who recruit peers, etc. • Recruits are linked by coupons with unique identifying numbers • Recruitment is limited through a minimum set of coupons • Incentives provided for completed survey and for each successful recruit

  21. Typical steps in an RDS survey

  22. Enrollment

  23. Interview

  24. Biological Testing

  25. Coupon Explanation

  26. Incentive Payment

  27. Recruitment Management

  28. Recruitment Management (2)

  29. RDS Assumptions • For most estimators, RDS is heavily assumption driven: • First order Markov Process (i.e., sampling occurs with replacement, sample becomes independent from the seeds) • Respondents know one another as members of the target population (and these are reciprocal) • Respondents are linked by a network composed of a single component • Respondents can accurately report their personal network size • Peer recruitment is a random selection from the recruiter’s network • Each respondent recruits a single peer

  30. RDS required data • Must collect each participant’s social network size • Must collect information about who recruited whom

  31. The importance of social networks in RDS • A participant’s social network size sets up the probability of someone being selected into the study • Must include all of the criteria used in eligibility • Only members of a participant’s social network should be recruited into study • Analysis is based on each social network member having an equal probability of being included in the study. • Adapt the question for A/KYP

  32. Where to get answers during formative assessment? • Go to A/YKP • Find leaders within the A/YKP target population • Talk to organizations working with A/YKP • Talk to gate keepers who may be involved with A/YKP

  33. What kinds of information should you get during formative assessment? • Network structure, characteristics of the population • Logistics, acceptability, identification of seeds

  34. Selecting ‘good’ seeds to start your study • Seeds are non-randomly selected members of the target population who • Are well regarded by their peers • Have large social networks and know diverse types of people • Can communicate well • Have some interest in the purpose of the survey

  35. Incentives • Find out the legal restrictions are about giving incentives to minors during research • Incentives are usually monetary but other types of incentives are fine • Find out what the population wants

  36. Coupons • Provide information about the survey (hours, location, benefits, etc.) • Track recruitment progress • Manage incentive payments • Link information about recruits and their recruiters through the ID numbering • Allows participants to be anonymous

  37. Analysis Software programs are available for free Available at www.hpmrg.org Available at www.respondentdrivensampling.org

  38. RDS strengths and challenges Challenges • Can be difficult to verify group membership • Uses incentives • Difficult to deal with selective non-response bias • Analysis is challenged and challenging • Relies on numerous assumptions Strengths • Representativeness • Efficient for hard to reach populations • Manuals and tools available • Peer recruit peers • No mapping needed • Allows for anonymity • Free computer software available

  39. Special Issues: RDS among A/YKP • Extra formative research • Assess social networks • RDS logistics and acceptance • Identify seeds • Mobility of A/YKP • Simple coupon designs (pictures) • Modified network size question • A/YKP appropriate incentives • Toys and activities in waiting room (one staff member) • What to do with family members/friends who want to go to interview site

  40. Special Issues for A/YKP in any sampling method • Include social worker with specialization in A/YKP at interview site • Conduct community meetings and involvement of organizations, concerned adults who may or may not be parents or guardians • Questionnaire design-PILOT • A/YKP of 14 years interpret questions differently than A/YKP of 21 years • Think about communications with police • Ethical considerations

  41. Resources • Johnston, L. G. Introduction to Respondent Driven Sampling. 2013. Geneva, Switzerland. http://applications.emro.who.int/dsaf/EMRPUB_2013_EN_1539.pdf • NetDraw and RDS Analyst Software Manual. http://applications.emro.who.int/dsaf/EMRPUB_2014_EN_1686.pdf?ua=1 • www.hpmrg.org (RDS Analyst Software) • www.respondentdrivensampling.org (RDSAT, references, RDS materials) • www.lisagjohnston.com (resource materials, journal articles, etc.) • Young Key Populations at Higher Risk of HIV in Asia and the Pacific: Making the case with Strategic Information. http://www.unicef.org/eapro/Young_key_populations_at_high_risk_of_HIV_in_Asia_Pacific.pdf

  42. Thank You

More Related