Table 2.
Frequency of optimisation constraints (%) by optimisation target and study design
| Optimisation target | Constraint (n %) | ||||||
|---|---|---|---|---|---|---|---|
| Study design | N studies | Cost | Time | Complexity | Burden | All active components | Other |
| Implementation | 39 | 18 (46%) | 6 (15%) | 8 (21%) | 5 (13%) | 15 (38%) | 2 (5.1%) |
| Factorial | 9 | 2 | 0 | 2 | 0 | 8 | 0 |
| Fractional factorial | 1 | 0 | 0 | 0 | 0 | 1 | 0 |
| Cluster RCT1 | 3 | 2 | 2 | 1 | 0 | 1 | 0 |
| RCT1 | 3 | 3 | 1 | 0 | 1 | 0 | 0 |
| Crossover | 2 | 1 | 0 | 0 | 0 | 1 | 0 |
| Pre-post | 18 | 9 | 2 | 5 | 2 | 4 | 2 |
| Other | 3 | 1 | 1 | 0 | 2 | 0 | 0 |
| Intervention | 142 | 60 (42%) | 14 (9.9%) | 7 (4.9%) | 50 (35%) | 53 (37%) | 2 (1.4%) |
| Factorial | 58 | 17 | 2 | 2 | 10 | 38 | 1 |
| Fractional factorial | 7 | 2 | 0 | 0 | 0 | 5 | 1 |
| Cluster RCT1 | 4 | 2 | 1 | 0 | 1 | 1 | 0 |
| RCT1 | 43 | 30 | 6 | 2 | 21 | 2 | 0 |
| Crossover | 14 | 2 | 1 | 0 | 11 | 2 | 0 |
| Pre-post | 4 | 2 | 2 | 2 | 4 | 0 | 0 |
| SMART | 5 | 2 | 2 | 1 | 2 | 1 | 0 |
| Other | 7 | 3 | 0 | 0 | 1 | 4 | 0 |
| Both | 2 | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | 1 (50%) | 0 (0%) |
| Factorial | 2 | 0 | 0 | 0 | 0 | 1 | 0 |
| Total | 183 | 78 (43%) | 20 (11%) | 15 (8.2%) | 55 (30%) | 69 (38%) | 4 (2.2%) |
1RCT Randomised control trial