One significant mechanism that causes incarcerations is the plea bargain process. For those that don't understand this, it basically is a method that generally offers an agreement for a lesser sentence than would be likely should the case go to trial and the accused is found guilty. On the surface, this seems like a reasonable approach. However, there are many arrests where numerous charges are in the report, and often, law enforcement has a propensity to identify as many charges as possible even if some are guesses or worse. The theory here is that if one is arrested for multiple charges, at least some should stick. The problem this creates is that the accused now has two choices. One is to fight all the charges at trial or the other is to take a lesser sentence through a plea bargain.

It is very possible the plea bargain will contain charges for crimes never committed that were simply "stack on" charges. But once these are in the system, they are very real and the accused must accept these in the plea bargain or attempt to prove innocence at trial. It really makes no difference whether or not these "stack on" crimes were ever committed at all. Whatever is in the arrest report, will generally be assumed as valid by the majority of prosecutors.

It is very difficult to reject a plea bargain if many charges were dropped. If one goes to trial, the majority of jurors will think that if numerous charges exist, at least some must be valid and they are much more likely to declare guilt on a few of the charges, even when evidence is sparse, just from simple math. Other factors that add pressure to accept a plea bargain include jail without bond, the reputation of the prosecutors and judges and that plea bargains are generally offered for a short time pressuring the accused to make a quick decision.

These and other aspects of the plea bargain process place great pressure on individuals to accept a plea bargain even if they are not guilty of charges. If one searches for the percentage of incarcerated people due to plea bargain versus trial, the data will be hard to find, but a large percentage of incarcerations follow this process. It is very difficult to determine the percentage of people incarcerated for crimes they actually committed versus "stack on" crimes but the plea bargain process nearly guarantees a fair percentage of the prison population did not commit all of the crimes on their record.