This analysis focuses on the impact of TIS legislation on the length of time inmates will serve and the affect that release at an older age will have on offenders' recidivism rates. Results of the analyses indicate that the impact of TIS on prison length of stay will vary across offenders. For example, the legislation would significantly increase length of stay for convicted murderers, but would extend the sentences of less serious offenders only to a minimal degree. The impact of TIS on age at release and recidivism would also vary across offenders. TIS would increase age at release for offenders convicted of sexual and personal offenses, and would likely reduce their recidivism rates. If TIS is implemented across the board, Illinois correctional officials expect that the prison population would increase by 45,000 inmates over the next 10 years, requiring the construction of 28 new 1,600-bed facilities. If TIS were implemented only for those offenders whose lengths of stay would be most affected, the prison population would increase by only 2,496 inmates over the next decade. 6 tables and 6 figures