An Empirical Comparison of Respondent-driven Sampling, Time Location Sampling, and Snowball Sampling for Behavioral Surveillance in Men Who Have Sex with Men, Fortaleza, Brazil
Obtaining samples of populations at risk for HIV challenges surveillance, prevention planning, and evaluation. Methods used include snowball sampling, time location sampling (TLS), and respondent-driven sampling (RDS). Few studies have made side-by-side comparisons to assess their relative advantages. We compared snowball, TLS, and RDS surveys of men who have sex with men (MSM) in Forteleza, Brazil, with a focus on the socio-economic status (SES) and risk behaviors of the samples to each other, to known AIDS cases and to the general population. RDS produced a sample with wider inclusion of lower SES than snowball sampling or TLS—a finding of health significance given the majority of AIDS cases reported among MSM in the state were low SES. RDS also achieved the sample size faster and at lower cost. For reasons of inclusion and cost-efficiency, RDS is the sampling methodology of choice for HIV surveillance of MSM in Fortaleza.
KeywordsSampling hidden populations Respondent-driven sampling Brazil Behavioral surveillance Sexual behavior HIV
We wish to acknowledge the support of the University of California, San Francisco, Center for AIDS Prevention Studies, U.S. National Institute of Mental Health (NIMH), P30 MH062246; AIDS International Training in Research Program (AITRP), Fogarty International Center, D43TW00003; and the International Traineeships in AIDS Prevention Studies, U.S. NIMH, R25MH064712. This work was supported by the National AIDS Prevention Program of the Brazilian Ministry of Health and the Centers for Disease Control-Global AIDS Program through the University Technical Assistance Project, Tulane University (U62/CCU622410-01).
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