Incarceration rates remained relatively constant during much of the 20th century and began increasing rapidly in the 1970’s as a result of policy changes. Fear of crime--not rising crime--is one factor responsible for the rising incarceration rates. Changes in laws have increased average sentence lengths. Increased prosecution and conviction of sex offenders, as well as longer and harsher sentences, have also contributed significantly to prison population growth. Local jails and some prisons also have been affected by the rising number of people released from facilities for persons with mental illnesses. In addition, parole boards have tightened release criteria, often in response to political pressure, and Virginia as abolished parole. Policies called truth in sentencing have also increased prison populations. A possible response to the issue of rising inmate populations is the use of sentencing guidelines that incorporate concerns about the growth of inmate populations. 53 reference notes