News and Analysis
March 20, 2015

CONTACT:    Kathy Saltmarsh
Executive Director

The Illinois Sentencing Policy Advisory Council is a statutorily created council of criminal justice stakeholders.  The Council is mandated to provide analysis of the fiscal impact of sentencing proposals on units of state and local government and to support through data analysis the implementation of evidence-based practices in the corrections arena.  


  • Develop and implement the first statistical model in the country designed to produce system-wide fiscal impact statements for sentencing policy and legislative proposals. 
  • Fully implement the Pew-MacArthur Results First Cost-Benefit Analysis Model; reverse engineer model to calculate criminal justice impacts of policies in social and human service arenas.
  • Develop and implement strategic plans for research initiatives and fiscal policy analysis of legislative and policy proposals; supervise research staff.
  • Write research reports and present findings to various groups and agencies; interact with decision makers from the executive, legislative and judicial branches of government in addition to state agency staff and advocacy organizations.


Trends Analysis: Unlawful Use of a Weapons
September 19, 2014

Using descriptive statistics to analyze trends gives a very broad picture of changes in crime and punishment over time. This analysis compares descriptive statistics with legislative actions that changed sentences for unlawful use of weapon offenses. More complex statistical analysis and hypothesis testing would be needed to establish causal relationships between policy actions and changes in crime, incarceration, or recidivism rates over time. In order to verify a causal relationship the study would have to control for a variety of key factors by examining data from economic, public health, education, and other sectors.

Download the Trends Analysis (PDF) >>


Average Offender Profiles
August 22, 2014

Sentencing policy is often driven by high-profile, extreme cases, but most of the offenders we incarcerate are not extreme cases.  To focus the discussion on the “Average Joe,” SPAC utilized several data sources to create these snapshots of average offenders in several offense categories.

These snapshots have no predictive value.   These snapshots are not meant to affect decisions in individual cases.  In each category there are people who fall outside the average profile.  Nonetheless, the recurring themes in terms of race, educational attainment, and recidivism are important for understanding broad outcomes of our sentencing policies.  SPAC offers these profiles to stimulate the discussion of how we are using incarceration and what we want our prison system to accomplish. 

IDOC Admissions, Exits, and Stock Population
August 22, 2014

These pie charts illustrate that while low level felonies account for a high number of admissions and exits, they do not remain in the IDOC population long enough per conviction to be a driver of the total population.

Download the pie charts (PDF) »

Infographic: Prison Resource Consumption by Offense Class
August 22, 2014

The larger the figure, the longer the average stay and the greater the magnitude of resources used. The figures are scaled to the violent Class 1 offenders’ length of stay, meaning First Degree Murder offenders take 5.2 times as many resources as violent Class 1 offenders and nonviolent Class 4 offenders take 1/10th as many resources.

To illustrate how different offense classes consume resources, SPAC analyzed the data for the average number of exits in each class for 2011, 2012 and 2013. Each figure represents 100 offenders. Resources consumed are expressed in bedyears and dollars. The per capita cost for housing one inmate for one year is $21,600, which was multiplied by the bedyears consumed by the entire offense class.

Download the infographic (PDF) »

Research Briefing Update

Drivers of the Sentenced Population: MSR Violators

Drivers of the Sentenced Population: MSR Violators

Over the past 22 years, the impact on Illinois’ prison admissions and population of those on Mandatory Supervised Release (MSR) returned to prison as technical violators or with new prison sentences has varied considerably.

Research Briefing Update

Drivers of the Sentenced Population: Probation Analysis

Drivers of the Sentenced Population: Probation Analysis

Under Illinois' sentencing structure, the majority of those convicted of a felony can be sentenced to either supervision in the community under probation or a period of incarceration within Illinois’ prison system.

Research Briefing Update

Drivers of the Sentenced Population: Length of Time Served In Prison

Drivers of the Sentenced Population: Length of Time Served In Prison

The length of time individuals serve in prison is affected by several factors, including changes in the legal classification of crimes and the sentences available for those crimes, pretrial detention practices, prosecutorial charging and plea decisions, judicial sentencing decisions, and policies and practices that impact the ability of correctional administrators to award good conduct and other sentencing credits.