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Methadone Treatment of Heroin Addicts

Keywords: censored data, Cox regression.


The data are the times, in days, that heroin addicts spend in a clinic. There are two clinics and the covariates are believed to affect the times spent in the clinic by addicts.

 Variable   Description
Clinic 1 or 2
Status 0 = still in clinic at end of study (censored) or 1 = departed from clinic
Time days spent in clinic
Prison 1 = prison record or 0 = no record
Dose methadone dosage (mg/day)


Data file (tab-delimited text)


Caplehorn, J. (1991). Methadone dosage and retention of patients in maintenance treatment. Medical Journal of Australia, 154, 195-199.
Hand D.J., Daly F., Lunn A.D., McConway K.J., Ostrowski E. (1994). A Handbook of Small Data Sets. London: Chapman and Hall.


This can be used as an interesting example of stratified Cox regression where stratification is done by clinic.



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