title: Availability and Quality of Size Estimations of Female Sex Workers, Men Who Have Sex with Men, People Who Inject Drugs and Transgender Women in Low- and Middle-Income Countries.
abstract: To assess the availability and quality of population size estimations of female sex workers (FSW), men who have sex with men (MSM), people who inject drug (PWID) and transgender women.
  
  
  
  Size estimation data since 2010 were retrieved from global reporting databases, Global Fund grant application documents, and the peer-reviewed and grey literature. Overall quality and availability were assessed against a defined set of criteria, including estimation methods, geographic coverage, and extrapolation approaches. Estimates were compositely categorized into 'nationally adequate', 'nationally inadequate but locally adequate', 'documented but inadequate methods', 'undocumented or untimely' and 'no data.'
  
  
  
  Of 140 countries assessed, 41 did not report any estimates since 2010. Among 99 countries with at least one estimate, 38 were categorized as having nationally adequate estimates and 30 as having nationally inadequate but locally adequate estimates. Multiplier, capture-recapture, census and enumeration, and programmatic mapping were the most commonly used methods. Most countries relied on only one estimate for a given population while about half of all reports included national estimates. A variety of approaches were applied to extrapolate from sites-level numbers to national estimates in two-thirds of countries.
  
  
  
  Size estimates for FSW, MSM, PWID and transgender women are increasingly available but quality varies widely. The different approaches present challenges for data use in design, implementation and evaluation of programs for these populations in half of the countries assessed. Guidance should be further developed to recommend: a) applying multiple estimation methods; b) estimating size for a minimum number of sites; and, c) documenting extrapolation approaches.
authors.affiliation: Strategic Information and Evaluation Department, the Joint United Nations Programme on HIV/AIDS, Geneva, Switzerland.
authors.forename: Keith
authors.initials: K
authors.lastname: Sabin
authors.affiliation: Technical Advice and Partnerships Department, The Global Fund to fight AIDS, Tuberculosis and Malaria, Geneva, Switzerland.|Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, China.
authors.forename: Jinkou
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of HIV/AIDS, World Health Organization, Geneva, Switzerland.
authors.forename: Jesus Maria
authors.initials: JM
authors.lastname: Garcia Calleja
authors.affiliation: Technical Advice and Partnerships Department, The Global Fund to fight AIDS, Tuberculosis and Malaria, Geneva, Switzerland.
authors.forename: Yaou
authors.initials: Y
authors.lastname: Sheng
authors.affiliation: Strategic Information and Evaluation Department, the Joint United Nations Programme on HIV/AIDS, Geneva, Switzerland.
authors.forename: Sonia
authors.initials: S
authors.lastname: Arias Garcia
authors.affiliation: Technical Advice and Partnerships Department, The Global Fund to fight AIDS, Tuberculosis and Malaria, Geneva, Switzerland.
authors.forename: Annette
authors.initials: A
authors.lastname: Reinisch
authors.affiliation: Technical Evaluation Reference Group Support Team, The Global Fund to fight AIDS, Tuberculosis and Malaria, Geneva, Switzerland.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Komatsu
mesh_terms: D000068598:Data Accuracy; D016208:Databases, Factual; D003906:Developing Countries / Q000191:economics; D005260:Female; D018451:Homosexuality, Male / Q000706:statistics & numerical data*; D006801:Humans; D007182:Income / Q000145:classification; D008297:Male; D011156:Population Density; D044382:Population Groups / Q000706:statistics & numerical data*; D012107:Research Design; D060386:Sex Workers / Q000706:statistics & numerical data*; D015819:Substance Abuse, Intravenous / Q000453:epidemiology*; D063106:Transgender Persons / Q000706:statistics & numerical data*