title: [The impact of different markers regarding the estimation of population size under capture-recapture method on men who have sex with men].
abstract: OBJECTIVE
  To discuss the impact of different markers on the estimation of MSM using the capture-recapture method.
  
  
  METHODS
  From March to July 2013, MSM were captured from the their related network to estimate the site of this population, under the capture-recapture method. Two different markers were set in the process of first 'capture'.
  
  
  RESULTS
  The estimated numbers of MSM in Beijing were 239 258 (95% CI:48 932-429 584) and 115 731 (95% CI:78 153-153 309) when using the two markers under capture-recapture method.
  
  
  CONCLUSIONS
  The estimated size of MSM population varied greatly under different markers which called for the right selection on markers when using the capture-recapture method to estimate the size of specific population.
authors.affiliation: Beijing Center for Disease Control and Prevention, Beijing 100013, China. Email: 1176299239@qq.com.
authors.forename: Guiying
authors.initials: G
authors.lastname: Li
authors.affiliation: Beijing Center for Disease Control and Prevention, Beijing 100013, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Lu
authors.affiliation: Beijing Center for Disease Control and Prevention, Beijing 100013, China.
authors.forename: Yanming
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Beijing Center for Disease Control and Prevention, Beijing 100013, China.
authors.forename: Shufang
authors.initials: S
authors.lastname: He
authors.affiliation: Beijing Center for Disease Control and Prevention, Beijing 100013, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Ma
authors.affiliation: Beijing Center for Disease Control and Prevention, Beijing 100013, China.
authors.forename: Xiong
authors.initials: X
authors.lastname: He