When I'm working inside the prison as a prison physician, all I see over time are the failures, as do the prison staff, because we see people coming back when they're not doing well. When people don't come back to prison, you don't know if it's because they're doing well or that they've died. So it's a difficult position to be in to see whether it's successful. My own understanding from the medical point of view is that methadone is the only medical option we have for heroin treatment. So just anecdotally, seeing people come in if they're on methadone maintenance treatment, I know they are not as ill as if they're using heroin on the street.
I don't know if I'm answering.... I'm not quite sure what's underlying your question and what you really want me to get at.