The Working Group consisted of State legislators, corrections and court officials, and other stakeholders in the criminal justice system. The Working Group reviewed analyses conducted by the Council of State Governments Justice Center (CSG Justice Center) in partnership with The Pew Charitable Trusts and the U.S. Justice Department's Bureau of Justice Assistance (BJA). The legislation proposed by the Working Group and signed into law in May 2013, implements policy changes developed through "justice reinvestment," a data-driven approach designed to improve public safety, reduce corrections spending, and reinvest savings in strategies that can decrease crime and reduce recidivism. The law (SB 371) has three key provisions. One provision requires supervision agencies to use risk assessment to inform supervision practices and to respond to violations with swift, certain, and more cost-effective sanctions. Second, the law mandates that people sentenced to prison for violent felony offenses receive supervision after release. Third, it provides community-based treatment for people on supervision with substance abuse treatment needs. The law stemmed from data analysis that determined the major driver of recent growth in the State's prison population was the number of people whose community-based supervision was revoked, as well as the length of time they spent in prison once re-incarcerated. The analysis also determined that the number of people who completed their sentences in prison and returned to the community without any post-release supervision increased significantly. Also, failure to adhere to the terms of probation or parole often stemmed from an individual's substance use and addiction and contributed to the growing prison population. 3 figures