Who knows your HIV status II? Information propagation within social networks of seropositive people

We seek to explain on what basis people choose to tell stigmatizing information about themselves to others. In particular, are there any rules governing how such decisions are made? We asked 70 HIV-positive individuals whether they knew various items of knowledge about their network members, and vice versa. These items range from things which might be known easily (e.g., marital status), things which are more difficult to know (e.g., blood type), to potentially stigmatizing information such as criminal record and HIV status. The information that one person knows about another may predict whether the latter's HIV status is also known. We examine this question using a combination of ethnography and decision trees. Even an apparently simple decision - whether or not to tell someone that you are seropositive - turns out to be complicated; yet the complexity can be extracted from open-ended interviews.