Table 1 Progression criteria for feasibility metrics
|  | GO–proceed with RCT | AMEND–proceed with changes | STOP–do not proceed unless changes are possible |
|---|---|---|---|
Recruitment target | n = 46 | n = 36–45 | n < 36 |
Adherence |  ≥ 90% of tDCS sessions are completed by participants who complete all assessments | 70–89% of tDCS sessions are completed by participants who complete all assessments |  < 70% of tDCS sessions are completed by participants who complete all assessments |
Participant retention |  ≥ 90% retention | 80–89% retention |  < 80% retention |
Optional MRI target |  ≥ 20% of participants have successful MRIs in each group | 10–19% of participants have successful MRIs in each group |  < 10% of participants have successful MRIs in each group |