We've seen the typical sentence length decease and the amount of time served shorten over the last decade or two. That's one of the reasons why the Correctional Service was motivated to develop this new program strategy. If sentence length is shorter and you want people to gain some benefit, you need to move them into programs more quickly.
It always troubles me when I hear that somebody is going to be given a federal penitentiary sentence for the sole purpose of receiving a program, treatment, or health care. It seems to be a very expensive way of providing that kind of treatment or intervention. It could even be very counterproductive, because so many things happen in the correctional environment that could get in the way of delivering the program.
I would not support the conclusion that lengthening a sentence automatically means better access and a better chance of completing a program.