Table 1.
Demographic Characteristics and Retention Rates by Group
| Groupa |
||||
|---|---|---|---|---|
| Variable | NC | MS | CS | CH |
| Age (in years; M ± SD) | 38.7 ± 8.7 | 38.2 ± 6.8 | 37.6 ± 8.8 | 33.9 ± 8.8 |
| Gender | ||||
| Female | 45% | 30% | 47% | 55% |
| Male | 55% | 70% | 53% | 45% |
| Race | ||||
| African American | 40% | 45% | 47% | 60% |
| Other | 60% | 55% | 53% | 40% |
| Heroin use (in years; M ± SD) | 10.3 ± 6.9 | 10.1 ± 6.5 | 9.4 ± 6.9 | 8.5 ± 8.3 |
| Cocaine use (in years; M ± SD) | 9.5 ± 6.9 | 8.2 ± 7.1 | 8.7 ± 7.5 | 7.3 ± 7.2 |
| Days heroin useb (M ± SD) | 29.1 ± 4.9 | 30 ± 0 | 29.6 ± 1.7 | 28.6 ± 6.2 |
| Days cocaine useb (M ± SD) | 15.9 ± 10.5 | 17.7 ± 8.8 | 14.1 ± 9.6 | 16.5 ± 9.9 |
| IQ (M ± SD) | 93 ± 8.1 | 97 ± 8.4 | 93 ± 7.6 | 95 ± 9.2 |
| Years of education (M ± SD) | 11.5 ± 1.5 | 11.6 ± 1.2 | 11.1 ± 1.4 | 11.7 ± 1.7 |
| Legal incomeb (M ± SD) | 521 ± 752.9 | 514 ± 798.9 | 502 ± 757 | 542 ± 790.4 |
| Study retention (weeks; M ± SD) | 22.0 ± 5.7 | 20.9 ± 7.1 | 20.5 ± 7.3 | 22.2 ± 5.3 |
Note. NC = noncontingent; MS = manual (contingent) group; CS = computerized standard-density (contingent) group; CH = computerized high-density (contingent) group.
a
There were no significant differences between groups on the measures listed (p > .05).
b
In the last 30 days before admission.