Participants most preferred frequency and method of contact for future studies
| Preferences | Frequency |
| Frequency of contact (able to select>1 option) | |
| Daily, n (%) | 5 (18.5) |
| Weekly, n (%) | 14 (51.9) |
| Every 2 weeks, n (%) | 22 (81.5) |
| Every month, n (%) | 22 (81.5) |
| Do not know, n (%) | 1 (3.7) |
| Preferences for method of contact (able to select>1 option) | |
| Email link to online survey, n (%) | 21 (77.8) |
| Direct response to email, n (%) | 16 (59.3) |
| Study app, n (%) | 20 (74.1) |
| Direct response by text message, n (%) | 20 (74.1) |
| Face-to-face interview, n (%) | 21 (77.8) |
| Paper questionnaire by post, n (%) | 26 (96.3) |
| Over the phone, n (%) | 18 (66.7) |
| Most preferred method of contact (select only one option) | |
| Email link to online survey, n (%) | 2 (7.4) |
| Study app, n (%) | 6 (22.2) |
| Direct response by text message, n (%) | 3 (11.1) |
| Face-to-face interview, n (%) | 7 (25.9) |
| Paper questionnaire by post, n (%) | 3 (11.1) |
| Over the phone, n (%) | 2 (7.4) |
| Missing, n (%) | 4 (14.8) |