Table 2.
Contingency management intervention metrics
| Metrica | Participants (n = 70)b |
|---|---|
| % Visits attended, mean (SD); median (IQR) | 37 (1.4); 25 (8-54) |
| % Visits attended, n (%) | |
| 0% | 4 (6) |
| 1-25% | 32 (46) |
| 26-50% | 15 (21) |
| 51-75% | 10 (14) |
| 75-99% | 6 (9) |
| 100% | 3 (4) |
| % Metabolite-free urine samples out of those attended, mean (SD); median (IQR) | 75 (3.6); 85 (0.5-1.0) |
| % Metabolite-free urine samples out of total possible visits, mean (SD); median (IQR)b | 29 (1.3); 18 (8-42) |
| % Metabolite-free urine samples, n (%)c | |
| 0% | 7 (10) |
| 1-25% | 37 (53) |
| 26-50% | 13 (19) |
| 51-75% | 5 (7) |
| 75-99% | 6 (9) |
| 100% | 2 (3) |
| Number of continuous metabolite-free samples, mean (SD); median (IQR)c | 4.2 (5.5); 2 (1-5) |
| Number of continuous metabolite-free samples, n (%)c | |
| Never submitted a metabolite-free sample | 7 (10) |
| Submitted only single, non-consecutive metabolite-free samples | 25 (36) |
| 2-8 | 28 (40) |
| 9-12 | 4 (6) |
| 13-24 | 6 (9) |
| Earnings, US$ mean (SD); median (IQR) | 112 (138); 50 (15-150) |
IQR, interquartile range; SD, standard deviation.
aData are n (%) unless otherwise noted.
b63 participants had 24 possible visits, 5 participants had 36 possible visits, 1 participant had 33 possible visits, and 1 participant had 25 possible visits (mean = 25 visits).
cWe assumed that during visits the participant did not attend, he would have submitted a urine sample positive for methamphetamine or cocaine metabolites.