Together with the GWU faculty and staff, the FI will assist research faculty and staff in implementing the study. Under the supervision of the Field Supervisor and in concert with the Principal Investigator and Study Coordinator, the FI will conduct face-to-face interviews using a computerized interview system on a tablet and contribute to field research activities and data collection for the study in study clinic and mobile van settings, including but not limited to survey data collection and HIV counseling and testing. FIs may also participate in other in-person research support activities as requested. The majority of the work will take place off campus.