Results revealed that instead of the 2-year cycle of admissions and releases and average stays of 2 years in prison, as indicated by release data alone, the Arizona prison system is actually working on a 5-year cycle in which a typical committed offender can expect to stay in prison 5.1 years before release. Findings indicated that the longer cycle is due to mandatory sentencing and that as a result, Arizona ranks high nationally in the extent of punitiveness for those imprisoned for felonies. In addition, although Arizona's average prison sentence of 6.4 years is almost identical to the national average of 6.3 years, Arizona inmates can expect to serve a much higher percentage of the sentence given than do inmates nationally. For most categories of criminal offenses, inmates are serving significantly more time under the new criminal code than under the old code. As of June 30, 1991, the 7,914 inmates serving mandatory sentences accounted for 52.2 percent of the active prison population. The full impact of the new code on prison population will not occur until sometime in the next decade. In addition, the impact of the law that took effect in September 1990 and that prohibits the earning of good time credits by inmates serving mandatory sentences has not yet been estimated and will extend beyond the impacts already studied. Tables