Epidemiological challenges to the assessment of HIV burdens among key populations: respondent-driven sampling, time–location sampling and demographic and health surveysSabin, Keith M.a; Johnston, Lisa G.bCurrent Opinion in HIV and AIDS: March 2014 - Volume 9 - Issue 2 - p 101–106 doi: 10.1097/COH.0000000000000046 EPIDEMIOLOGY: CONCENTRATED EPIDEMICS: Edited by Chris Beyrer, Stefan D. Baral, and Patrick S. Sullivan Abstract Author Information Purpose of review Measuring the burden of HIV among key populations is subject to many challenges. Sufficient quantities of valid HIV prevalence and programme coverage data are required to effectively respond to the epidemic. Recent findings Ability to validate exposure to unprotected sex through the innovative use of prostate-specific antigen provides confirmation of condom use. A new weighting scheme based on frequency of venue attendance for time location samples should improve validity of data obtained with this method. Two new proportion estimators, new diagnostic methods, a new population size estimator and new analysis software will provide more robust results from respondent-driven sampling (RDS). Summary Analytical advances have improved the potential quality of results from surveys using time location and RDS. However, data from sufficient numbers of sites over sufficient number of years are still needed to provide clear national pictures of distribution and trends of HIV infection. aUNAIDS, Geneva Switzerland bGlobal Health Sciences, University of California, San Francisco, California, USA Correspondence to Keith M. Sabin, 20, avenue Appia, CH 1211 Geneva 27, Switzerland. Tel: +1 41227915570; e-mail: firstname.lastname@example.org Copyright © 2014 Wolters Kluwer Health, Inc. All rights reserved.