1. Referral to study team by health authorities | |
 – Collaborate with referral partners to obtain participant contact information, preferred modes and times of contact, consent for initial contact | |
 – Assign each participant to one field interviewer throughout the study, where possible | |
2. Initial contact (telephone) | |
 – Contact participant using study cell phone with text and email functions | |
 – Use different modes and times of contact and obtain three alternative contacts | |
 – Answer questions and offer flexibility in timing and location of interview | |
 – Provide 24-h reminders using preferred communication mode (e.g., text messages) | |
 – Enquire at each encounter if there is a change in contact information | |
 – Accommodate interview rescheduling | |
3. Baseline interview (in-person) | |
 – Establish rapport using effective communication techniques | |
 – Adopt a professional (neutral, non-judgmental) manner | |
 – Apply risk-mitigation training (interviewer safety) | |
 – Provide essential study materials outlining the research process and interview dates | |
 – Explain study purpose and confidentiality, answering questions and providing time to consider | |
 – Use visual aids to convey the type, length and timing of research interviews | |
 – Verify eligibility and obtain written informed consent | |
 – Verify contact information and alternative contacts | |
 – Use audio aids for survey items sensitive to reporting bias | |
 – Provide meaningful honoraria such as gift cards for local department stores | |
 – Collect information to facilitate rapport at follow-up interviews, such as preferred name |