Oregon’s Justice Reinvestment Initiative (JRI), “is an approach to spending resources more effectively with the goals of reducing recidivism, decreasing prison use, protecting the public and holding offenders accountable (Oregon Criminal Justice Commission, 2019).” To maximize the effectiveness of Justice Reinvestment programs, policy makers need to understand the relationship between imprisonment, particularly length of stay (LOS), and recidivism. Subsequently, the Oregon Criminal Justice Commission (CJC) sought to conduct a LOS study in Oregon similar to a study completed by Snodgrass et al (2011). The goal of Portland State University’s (PSU) analysis is to provide useful information for Oregon’s JRI effort on the effectiveness and efficiency of incarceration. Specifically, PSU was charged with assessing the impact of length of prison stay on Oregon’s three official measures of recidivism - rearrest, reconviction, and reincarceration.