Table 3.
Engagement with the intervention among the participants who completed the welcome phase and received the intervention (n=15).
| Engagement metric | Values, mean (SD) | Values, median (IQR; range) |
| Number of substance tests prompted by the smartphone app | 24.9 (4.0) | 25 (23-28; 17-30) |
| Number of substance tests completed | 8.9 (7.1) | 6 (3.5-11; 2-26) |
| Number of substance tests showing recent methamphetamine and amphetamine abstinence | 2.7 (4.1) | 2 (0-3; 0-16) |
| Number of substance tests that were invalid | 0.5 (0.5) | 1 (0-1; 0-1) |
| Substance tests that were completed out of those prompted (%) | 35 (27) | 24 (16-41; 10-94) |
| Substance tests showing recent methamphetamine and amphetamine abstinence out of those prompted by the smartphone app (%) | 12 (22) | 7 (0-13; 0-89) |
| Substance tests showing recent methamphetamine and amphetamine abstinence out of those completed (%) | 31 (37) | 10 (0-61; 0-100) |
| CMa guide calls completedb | 5.6 (6.5) | 4 (0.5-8; 0-24) |
| CBTc modules completedd | 11.5 (11.2) | 7 (4.5-17; 0-35) |
| Rewards earned (intervention only; US $)e | 98.77 (60.38) | 91 (48.50-128.92; 37-236.38) |
| Rewards earned (research assessments; US $)e | 18.67 (16.63) | 10 (10-27.50; 0-45) |
| Rewards earned (total; US $)e | 117.44 (55.9) | 107.04 (85.95-138.92; 37-246.38) |
aCM: contingency management.
bParticipants were encouraged to complete 1 CM guide call per week for the 12-week program but could complete additional coaching calls as desired.
cCBT: cognitive behavioral therapy.
dA total of 35 CBT modules were available.
eParticipants could earn up to US $45 for completing research assessments plus US $280 in intervention rewards (US $325 total) if they enrolled before March 2022 or US $420 (US $465 total) if they enrolled in March 2022 or later.