There are 628 data points in the original data, 575 of which have no missing values.
Variable descriptions:
| Variable | Description | Codes/Values |
| ID | Identification Code | 1 - 628 |
| AGE | Age at Enrollment | Years |
| BECK | Beck DepressionScore | 0.000 - 54.000 |
| HC | Heroin/Cocaine Use During | 1 = Heroin & Cocaine |
| 3 Months Prior to Admission | 2 = Heroin Only | |
| 3 = Cocaine Only | ||
| 4 = Neither Heroin nor Cocaine | ||
| IV | History of IV Drug Use | 1 = Never |
| 2 = Previous | ||
| 3 = Recent | ||
| NDT | Number of Prior Drug Treatments | 0 - 40 |
| RACE | Subject's Race | 0 = White |
| 1 = Non-White | ||
| TREAT | Treatment Randomization | 0 = Short |
| Assignment | 1 = Long | |
| SITE | Treatment Site | 0 = A |
| 1 = B | ||
| LEN.T | Length of Stay in Treatment | Days |
| (Admission Date to Exit Date) | ||
| TIME | Time to Drug Relapse | Days |
| (Measured from Admission Date) | ||
| CENSOR | Event for Treating Lost to | 1 = Returned to Drugs |
| Follow-Up as Returned to Drugs | or Lost to Follow-Up | |
| 0 = Otherwise | ||
| Y | log of TIME | |
| ND1 | Component of NDT | |
| ND2 | Component of NDT | |
| LNDT | ||
| FRAC | Compliance fraction | LEN.T/90 for short trt |
| LEN.T/180 for long trt | ||
| IV3 | Recent IV use | 1 = Yes |
data(uis)A data frame with dimension 575 by 18.
Hosmer,D.W. and Lemeshow, S. (1998) Applied Survival Analysis: Regression Modeling of Time to Event Data, John Wiley and Sons Inc., New York, NY