Table 1.
Characteristics of host trials.
| ClinicalTrials.gov ID | Recruiting tobacco smokers | Recruiting people with HIV | Incorporated neuroimaging | Outcome was smoking cessation | Study duration (months) | Maximum monetary compensationa (US $) |
| NCT03438188 | ✓ |
|
✓ |
|
2 | 514 |
| NCT02837510 | ✓ |
|
✓ | ✓ | 4 | 810 |
| NCT03169101 | ✓ | ✓ |
|
✓ | 4 | 440 |
| NCT03384784 | ✓ | ✓ |
|
|
6 | 590 |
aParticipants randomized to the contingency management or information provision+contingency management conditions had the opportunity to “win” an additional US $120 at each visit. However, given the very low probability of this occurring (2.15×10–8), the maximum compensation for each host study is listed.