title: Theoretical and Empirical Comparisons of Methods to Estimate the Size of Hard-to-Reach Populations: A Systematic Review.
abstract: Worldwide, the HIV epidemic is concentrated among hidden populations (i.e., female sex workers, men who have sex with men, and people who inject drugs). To understand the true scope and scale of the HIV epidemic, estimates of the sizes of these populations are needed. Various methods are available to enumerate hidden populations, but the degree of agreement between these methods has not been formally evaluated. We systematically reviewed the peer-reviewed literature to assess the extent to which different population size estimation methods provide the same estimate of a target population. Of the 341 studies identified from our search, 25 met our eligibility criteria. Twenty-one unique methods were documented. The service multiplier method was the most common in the review. Eighty target populations were estimated, covering 16 countries. We observed variable population size estimates, with little agreement between methods. We note trends in the relative performance of individual methods.
authors.affiliation: Center for AIDS Prevention Studies, TAPS Fellowship Program, University of California, San Francisco, Mission Hall, 550 16th Street, 3rd Floor, Mail Code 0886, San Francisco, CA, 94158, USA. paul.wesson@ucsf.edu.|Department of Epidemiology, School of Public Health, University of California, Berkeley, Berkeley, CA, USA. paul.wesson@ucsf.edu.
authors.forename: Paul
authors.identifier: http://orcid.org/0000-0002-7033-1038
authors.initials: P
authors.lastname: Wesson
authors.affiliation: Department of Epidemiology, School of Public Health, University of California, Berkeley, Berkeley, CA, USA.
authors.forename: Arthur
authors.initials: A
authors.lastname: Reingold
authors.affiliation: Department of Epidemiology, University of California, San Francisco, San Francisco, CA, USA.
authors.forename: Willi
authors.initials: W
authors.lastname: McFarland
mesh_terms: D055030:Drug Users / Q000706:statistics & numerical data*; D005260:Female; D015658:HIV Infections / Q000453:epidemiology*; D006301:Health Services Needs and Demand; D006801:Humans; D008297:Male; D011156:Population Density; D060386:Sex Workers / Q000706:statistics & numerical data*; D000072339:Sexual and Gender Minorities / Q000706:statistics & numerical data*; D015819:Substance Abuse, Intravenous
keywords: HIV/AIDS; Hidden populations; Men who have sex with men; People who inject drugs; Population size estimation