Recorded explanations for being unable or unwilling to participate, by site
| Main explanation (if given) for being unable or unwilling to participate | Site A | Site B | Site C |
| Declined participation, no reason recorded | 53 (40%) | 50 (44%) | 12 (24%) |
| Physical ill health of either person | 6 (5%) | 15 (13%) | 4 (8%) |
| ‘Managing fine’ reported | 11 (8%) | 6 (5%) | 11 (22%) |
| Time constraints reported | 25 (19%) | 24 (21%) | 11 (22%) |
| Other reasons recorded | 37 (28%) | 19 (17%) | 13 (25%) |
| Total potential participants recorded as unable or unwilling to participate | 132 | 114 | 51 |
NB percentages rounded to the nearest whole number.