In 1990, the North Carolina General Assembly created the Sentencing and Policy Advisory Commission to evaluate sentencing laws and policies and recommend any modifications necessary to achieve policy goals. As part of the mandate, the General Assembly required the Sentencing Commission to develop a correctional population simulation model. The model would be used to analyze any proposed change in the sentencing laws to estimate the impact on the inmate population.
Previously, the state enacted changes to sentencing laws without hard data about what correctional resources would be necessary to support those changes. Without enough resources to support the policies, prisons became overcrowded, offenders were released after serving only a fraction of their sentences and the public lost confidence in the criminal justice system. Lesson learned.
At the General Assembly’s behest, the Sentencing Commission began employing a model that used empirical information (conviction and sentence data) from the previous year to project future resource needs. The model could be used to project the overall prison population and the impact of proposed policy changes on that population. These projections became the guideposts for correctional funding and resources.
When the General Assembly or Secretary of the Department of Public Safety considers changes to the sentencing laws and policies, the Sentencing Commission is responsible for projecting the impact of the proposals. The Commission is required to apply the model to every bill and resolution introduced that propose any change in criminal law. For instance, changes to laws that increase penalties for violating existing laws or criminalize additional behaviors can lead to a net increase in the number of persons incarcerated and the duration of their incarcerations. Every legislative session, the Commission produces numerous impact projections. The General Assembly uses these projections to determine whether to pass a bill and appropriate more funds for prison resources or to make adjustments to the bill.
The Sentencing Commission also uses the correctional population simulation model to provide prison population projections. These projections, updated annually, give the General Assembly and the Department of Public Safety an estimate of what the prison population will be for the next ten years assuming there are no policy changes. This allows the State to plan for future criminal justice needs.
In 2011, the General Assembly passed the Justice Reinvestment Act, which made a number of substantive changes to the sentencing laws in North Carolina. It made the process more complex by adding some new sentencing options and changing the way the courts used some existing options. The Sentencing Commission needed a model that was more transparent, and would allow staff to make adjustments to take into account the variety and complexity of the changes.
The Commission, already using SAS for managing and analyzing data, turned to SAS for help with designing a new correctional population simulation model. The SAS Advanced Analytics Lab and SAS Operations Research Center of Excellence adapted the software for the new model. The programming was visible, allowing Commission staff to make adjustments as needed, aided by SAS’ ongoing support.
To date, the Commission has used the SAS model to produce two sets of prison population projections, which were published in February 2013 and February 2014. Initial results indicate that the projections are within the Commission’s historical accuracy range of 2%. Not only are the projections reliable, SAS has automated much of the process. In the future, the Commission hopes to adapt the model to project resource needs for other justice populations, particularly juvenile justice resources.
The work of the Sentencing Commission reinforces the importance of making decisions based on data. Reliable projections help policymakers understand the resource demands associated with their proposals. Having adequate resource needs to support criminal justice policies and to maintain public safety are key to bolstering the public’s confidence in the criminal justice system.
To learn more, please check out the Sentencing Commission’s 2013 SAS Global Forum presentation, Projecting Prison Populations with SAS Simulation Studio.
