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.

Menza et al. BMC Public Health 2010 10:774   doi:10.1186/1471-2458-10-774

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