Good time is an early release procedure under determinate sentencing regimes: prison inmates get an automatic reduction in sentence for every day they spend without being written up for a violation of prison rules. They may also earn reduced time by participating in educational programs, community service projects, or medical experiments. The idea is that model prisoners are less likely to re-offend, and that prisoners will behave better if they have an incentive not to cause trouble. Some prisoners will not be eligible for good time, due to the nature of their offenses.
The following is an example of a state statute authorizing good time:
"651:15-a Reduction in Sentence.
I. Any inmate whose conduct while in the state prison has been meritorious shall be entitled to a reduction of 1/3 off his or her minimum and maximum sentences. This reduction shall be awarded at the rate of 121 days per year. If an inmate commits one or more disciplinary infractions in a given year, he or she may be entitled to a portion of the reduction. The warden shall establish a system for evaluating whether an inmate's conduct in a given year warrants a sentence reduction of less than 121 days. Each inmate shall be annually informed of his or her sentence reduction credit. The warden shall issue a written explanation to any inmate not receiving the full 121 days of sentence reduction credit in a year and shall notify the inmate of the right to a hearing on the matter. Any sentence reduction time awarded to an inmate in a prior year shall not be taken away. "
"The following is an example of a Colorado law governing good time:
"17-22.5-301. Good time.
(1) Each person sentenced for a crime committed on or after July 1, 1979, but before July 1, 1981, whose conduct indicates that he has substantially observed all of the rules and regulations of the institution or facility in which he has been confined and has faithfully performed the duties assigned to him shall be entitled to a good time deduction of fifteen days a month from his sentence. The good time authorized by this section shall vest quarterly and may not be withdrawn once it has vested. No more than forty-five days of good time may be withheld by the department in any three-month period of sentence.
(2) Each person sentenced for a crime committed on or after July 1, 1981, but before July 1, 1985, shall be subject to all the provisions of this part 3; except that the good time authorized by this section shall vest semiannually and no more than ninety days of good time may be withheld by the department in any six-month period of sentence.
(3) Each person sentenced for a crime committed on or after July 1, 1985, shall be subject to all the provisions of this part 3; except that the good time authorized by this section shall not vest and may be withheld or deducted by the department.
(4) Nothing in this section shall be so construed as to prevent the department from withholding good time earnable in subsequent periods of sentence, but not yet earned, for conduct occurring in a given period of sentence."