The biggest difference between probation and parole is that probation is ordered by a judge and parole is ordered by a parole board when the person is already in jail. Probation is ordered when the behavior is good, if the crime is less serious, if the person has a job to go to for help in stabilizing his life, if the person can be trusted to go to a halfway house as ordered, if the mentally ill person has made a genuine commitment to take medication regularly and see their doctor, or if the judge has some reason to believe the person has made a positive change. Parole is given by a parole board when the person is already in prison, the crime is more serious, and the board has reason to feel the prisoner has made positive changes in behavior and habits which created trouble in the first place. Geography doesn't always have an effect on the decision though the support of positive family nearby may help sway the judge. Attending AA or NA if the person is chemically dependent is seen as a positive change. As a volunteer crisis counselor in a jail, one prisoner was given probation because he "spoke from my heart" about how having children had changed him and being a positive role model was now important. The commitment to stay away from old friends and habits can also sway a judge or board. The idea is to give the person some chance to change their outside behavior so that they don't return to prison.