“States across the country are increasingly seeking cost-effective and evidence-based strategies to enhance public safety and manage their corrections and supervision populations. One such effort emerged in the mid-2000s, when several states experimented with a criminal justice reform effort built on a foundation of bipartisan collaboration and data-driven policy development. This model-justice reinvest-ment-yielded promising results, supporting cost-effective, evidence-based policies projected to generate meaningful savings for states while maintaining a focus on public safety. In response to these early successes, Congress appropriated funds to the Bureau of Justice Assistance (BJA) to launch the Justice Reinvestment Initiative (JRI) in 2010 in partnership with the Pew Charitable Trusts (Pew). The initiative formalized the process and provided both financial support and in-kind technical assistance for states to engage in this work. This report describes the JRI model and the experiences and interim outcomes in 17 participating JRI states: Arkansas, Delaware, Georgia, Hawaii, Kansas, Kentucky, Louisiana, Missouri, New Hampshire, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, South Carolina, South Dakota, and West Virginia” (p. 1). Sections following an executive summary include: introduction; the JRI Model described; population and cost drivers and responses; projected and preliminary outcomes; reinvestment; challenges; and concluding remarks and implications. The appendix provides case studies of the 17 participating states.