Network Sampling

Network sampling is widely used when rare populations are of interest in survey research. Typically, sampling frames do not exist for rare populations [Page 507]because usually there is little information on the size and magnitude of the population. Two main methods can be employed in a survey with an unknown population: screening and salting. The first way is to screen for respondents of interest during the interview, and the second approach is to acquire sample units through officiai records or documents. Both approaches have shortcomings. Screening requires high costs. Salting entails difficulties with obtaining membership information, because officiai personnel records may be confidential. Network sampling is considered an alternative to the previous ways of estimating rare populations in which sampling frame is almost impossible to ...