The proposed method requires sampling from each respondent’s network connections, and matching these connections against both the other respondents in the sample and the list of their respective contacts. Such methods are not particularly complex, and make use of capture/recapture methods with a long history in both social and biological sciences. In current circumstances, however, considerable modifications are required, as network sampling in
the context of illicit and often socially stigmatized activity requires retaining anonymity of both research subjects and their network connections. These concerns necessarily complicate
the matching of contacts assumed by the capture-recapture methods. For this reason, a naïve matching strategy of simply matching the names of respondents and contacts across interviews is not possible. We address this challenge by a novel means of establishing network connections while maintaining
the anonymity of participants and their contacts which we refer to as the “telefunken method”.
This process requires the recruitment of a sample pool of network participants and the elicitation of a number of contacts from each. In addition to personal descriptives later used in the matching process, each participant was asked for his/her own “telefunken code”, derived from the last three digits of their own mobile phone number.