When the Iowa Statistical Analysis Center (SAC) found that increases in the prison population during 1978 were due to reduced paroles rather than increased admissions, the Iowa General Assembly set a cap on the prison population and called on the parole board to increase paroles. The statistical risk assessment information was made relevant to parole decisions. This assessment concludes that the SAC's guidelines have not only increased paroles, but also contributed to a 35-percent decrease in new violence among parolees. Statistical evidence does not support the popular belief that violence among parolees is a serious problem. Several studies in Iowa demonstrate that the potentially violent criminal can be identified with a high degree of accuracy: 88 percent of the violent crime charged to ex-prisoners can be traced to a predictable group of just 28 percent of those released. Iowa corrections are now identifying members of this group of potentially violent offenders through a formal evaluation process called risk assessment. Criminal code changes aimed at incapacitating the potentially violent offender can further reduce violent crime by ex-offenders without increasing the prison population. In addition, analysis of 559 offenders committed to Iowa prisons during 1981 suggests that 15 to 20 percent could be safely placed in community corrections programs. Tables, case histories of parolees, and forms used in the Parole Guidelines System are included.