Table 5 Participant re-engagement activities

1. Follow-up interviews (in-person or telephone)

 – Emphasize the value of participant’s contribution at each interview and review the study purpose

 – Provide breaks during lengthier interviews

2. Participant tracking and interview scheduling

 – Maintain the same field interviewer

 – Text reminders 1 week and 24 h prior to each interview

 – Attempt different modes/times/types of contact and alternative contacts (partner/friends/family)

 – Reminder of ongoing study eligibility even if previous interviews are missed

 – Offer flexibility in interview location and time and accommodate requests for rescheduling

 – Encourage participants to update team with changes in personal information

3. Specific tracking protocols

 – Identify new approaches, vary contact type and frequency, send re-engagement letter

4. Study team support

 – Review progress reports (completed or missed interviews, requests to withdraw)

 – Frequent field interviewer meetings and retention training