Background: Ethnographic mapping and enumeration systematically describe hidden populations. Our objective was to identify and describe male and transwomen sex work venues and venue-based sex workers in Lima, Peru.
Methods: PLACE, Priorities for Local AIDS Control Efforts, includes: brief community informant interviews to brainstorm possible venues; visits to possible venues to verify, map and describe the venue and estimate the number of people present at peak times using venue informant interviews; and surveys with venue attendees. We describe the PLACE data. We returned to verified venues for capture-recapture enumeration. We visited all venues on peak times at two points two weeks apart. At point 1, we offered a pocket calendar “tag” to MTSWs present and recorded the number accepting and rejecting the tag. At point 2, we recorded the number previously “tagged” and new MTSWs. We applied a population point estimate formula to the capture-recapture data and compared that with the PLACE estimates.
Results: We brainstormed MTSW sex work venues with 755 community informants, including taxi drivers, “sex hotel,” community business, socialization venue and health personnel, police and MTSWs. Informants named 1,754 venues, which were consolidated into 447 venues: 91 did not exist; 259 existed but are not MTSW venues; and 81 are MTSW venues. Of confirmed venues, 51% are street-based, 28 have only MSWs, 49 have only TSWs and 4 have MTSWs. We surveyed 259 TSWs, 129 MSWs and 102 clients. Venue personnel estimated 357 MSWs and 443 TSWs. Capture-recapture estimated 542 MSWs (95% CI: 475, 609) and 677 TSWs (95% CI: 635, 699).
Conclusions: PLACE is a highly systematic method for identifying and describing sex work venues and attendees and implementing the ethnographic mapping that precedes capture-recapture. Capture-recapture is more systematic – but more costly and time intensive – than PLACE for estimating the size of hidden populations.