In 1980, Illinois abolished parole and indeterminate sentencing, creating instead a system in which all inmates were eligible to receive day-for-day statutory good-time credits, which meant that inmates who behaved well could be released after serving 50 percent of their term. Statistical analyses indicate that, without these program, the Illinois correctional system would be housing a population 18 percent higher than it currently stands. The impact of shorter prison terms on recidivism rates was calculated using rearrest measures, arrests that occurred during the program's release window, and return-to-prison rates, which were very low. In general, the findings showed no significant decrease or increase in the Illinois crime rate that could be associated with the early release of prisoners or with shorter terms of imprisonment. This study found that the MGT and SMGT programs reduced the State's correctional costs by over $100 million, although law enforcement, courts, and local detention facilities did incur some additional costs. 7 tables, 8 notes, and 6 references