Respondents are given an incentive both for completing the questionnaire and for each respondent successfully recruited into the study.Ĭonvenience sampling through online surveys is now well established as a means for recruiting MSM, but there is little published research comparing Internet sampling among MSM with the use of RDS. Bias is minimised through the production of long recruitment chains whereby the sample is no longer dependent on the non-randomly selected initial participants. These three peers are asked to complete the survey and then recruit three more contacts and so on until the sample size is reached. Members of the target group are selected by the research team and, having completed the survey, they invite up to three peers from their social network who are also members of the target group to participate in the study. RDS is especially useful for HIV surveillance and has been used successfully to recruit representative samples of MSM throughout the world. Respondent driven sampling (RDS) is an alternative approach that was developed to recruit unbiased samples of hard to reach populations. However, convenience sampling is prone to biased estimates because the samples that are recruited are not representative of the population as a whole. Effective convenient sampling techniques among MSM include recruitment from sexual health clinics and gay venues and, more recently, through online surveys which are particularly efficient for reaching large numbers of geographically dispersed MSM. It is a cost-effective and easy method for recruiting non-representative samples of men who have sex with men (MSM). Convenience sampling is a non-probability sampling technique whereby respondents are recruited from a group of individuals that is readily available to the researcher.