While there is much debate regarding this subject, it is statistically accurate that individuals who are released from prison after a lengthy period of time, return to a life of crime rather quickly. In many cases their inability to get hired does have something to do with their criminal record, and although employers aren't supposed to base their decision solely upon such information, their thought process and their ultimate decision is based at least partially on an employees criminal history.
There are of course exceptions to this rule however and it should not be forgotten that those individuals who are properly rehabilitated often move on to live normal, crime free lifestyles. This being said, there are many, many more who tend to slip backward into their old patterns of criminal behavior and soon find themselves right back where they came from.
It has been stated by many people who have spent great lengths of time in prison that their incarceration behind bars did nothing else but to teach them to be better criminals, serving as a type of finishing school in essence. For example, someone who may enter prison for the theft of a television set may return to public life with a knowledge of how to manufacture drugs, have gained the knowledge to knock-off retail stores, or God forbid have discovered ways to commit murder and be able to stash the body in a way where it may never be found again.
Another factor that plays a part in their eventually return to prison is that in so few state run facilities there are little to no trades being taught to the prisoners, which in turn it makes it extremely difficult for them to find work once they have been released from incarceration.
This is a common reality for prisons, or even those who are serving time for nonheiness crimes such as stealing a cooling pie off of someone's back window sill. Throwing such a petty criminal in with some of the worst and most violent prisoners is really only a recipe for disastor because first and foremost it could quite easily lead to an assault upon the newcomer because any new inmate into the prison community becomes an immediate target for some of the more seasoned prisoners. In effect, prison time can easily turn well-educated petty thiefs into cold-blooded killers, and the education in crime that inmates receive there almost guarantees that they will return to prison within a short period of time, therefore making them a career prisoner.