title: Review of sampling hard-to-reach and hidden populations for HIV surveillance.
abstract: Adequate surveillance of hard-to-reach and 'hidden' subpopulations is crucial to containing the HIV epidemic in low prevalence settings and in slowing the rate of transmission in high prevalence settings. For a variety of reasons, however, conventional facility and survey-based surveillance data collection strategies are ineffective for a number of key subpopulations, particularly those whose behaviors are illegal or illicit. This paper critically reviews alternative sampling strategies for undertaking behavioral or biological surveillance surveys of such groups. Non-probability sampling approaches such as facility-based sentinel surveillance and snowball sampling are the simplest to carry out, but are subject to a high risk of sampling/selection bias. Most of the probability sampling methods considered are limited in that they are adequate only under certain circumstances and for some groups. One relatively new method, respondent-driven sampling, an adaptation of chain-referral sampling, appears to be the most promising for general applications. However, as its applicability to HIV surveillance in resource-poor settings has yet to be established, further field trials are needed before a firm conclusion can be reached.
authors.affiliation: Family Health International, Arlington, VA, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Magnani
authors.forename: Keith
authors.initials: K
authors.lastname: Sabin
authors.forename: Tobi
authors.initials: T
authors.lastname: Saidel
authors.forename: Douglas
authors.initials: D
authors.lastname: Heckathorn
mesh_terms: D004812:Epidemiologic Methods; D015658:HIV Infections / Q000453:epidemiology*; D006801:Humans; D018579:Patient Selection; D015995:Prevalence; D012309:Risk-Taking; D012494:Sampling Studies; D013997:Time Factors