Internal pilot progression criteria
| Progression criteria | Red (stop)* <66% | Amber (amend)† ≥66%–99% | Green (go)‡ 100% |
| Average recruitment rate/site/month | <0.7 | 0.7–1.0 | 1.1 |
| Sites open | <12 | 12–17 | 18 |
| Participants recruited | <50 | 50–96 | 97 |
*Red: halt, do not progress to main study.
†Amber: review areas of weakness and make amendments accordingly.
‡Green: no action required, continue to main study.