Statewide Shifts in the Use of Prison and Probation Sentences

The number of people in prison in Illinois fell almost 40% from 2010 to 2023, dropping from 48,418 to 29,828, reaching its lowest level since 1991 (30-plus years). While casual observers might assume that this drop in the prison population is primarily due to the recent COVID-19 pandemic, or to changes in prosecution policies specifically in Cook County, it is important to recognize that this has been a broad trend for a long time, predating the pandemic and driven by counties large and small, all over the state. It is a result not only of declines in arrests and convictions for felony-level offenses, but also of widespread changes in sentencing practices. To help practitioners, policy makers and the public understand these changes, Loyola’s Center for Criminal Justice created a data dashboard showing felony sentencing trends and patterns across individual counties, among judicial circuits, and between urban and rural communities in Illinois.

Under Illinois law, individuals convicted of First-Degree Murder and Class X felonies must be sentenced to prison. But most prison sentences in Illinois are imposed for other felony-level offenses—Class 1 through 4 felonies—for which a sentence to prison is not mandatory, and individuals can instead be sentenced to a period of community-supervision (i.e., probation). Between 2010 and 2023, sentences to prison for both “probationable” and “nonprobationable” felonies declined statewide. Prison sentences for First-Degree Murder and Class X felonies combined fell 11%; by 2023, they accounted for less than 15% of all sentences to prison. During the same period, sentences to prison for Class 1 through 4 felonies combined fell 44% and accounted for 87% of all sentences to prison in 2023.

In addition to this drop in the absolute number of people sentenced to prison for Class 1 through 4 felonies, the percent of all those convicted of these offenses who were sentenced to prison also fell. In 2010, roughly 45% of people convicted of a Class 1 through 4 felony were sentenced to prison; in 2023 just 34% were sentenced to prison.

It is important to note that these sentencing trends are very broad. Illinois is a diverse state, with 102 counties ranging from large urban to small rural communities. And criminal justice decision-making is highly localized, with elected prosecutors and judges making sentencing recommendations and decisions at the county level. And yet, between 2010 and 2023, most Illinois counties (roughly 70%-75% of the total) saw fewer people sentenced to prison and a smaller percent of people convicted of felonies being sentenced to prison. What this translates to is a reduced use of prison for Class 1 through 4 felonies, and an increased use in probation.

There has also been a change in the types of crimes for which people are being sentenced to prison. Generally, a larger share of those admitted to prison are being sentenced for violent crimes and/or more serious felony class offenses. Statewide, 19% of those sentenced to prison in 2010 were convicted of a violent crime; by 2023 that had increased to 36% of all sentences to prison. Likewise, a larger proportion of those sentenced to prison had been convicted of a firearm possession offense (i.e., illegal possession of a firearm, not the use of a firearm in the commission of a violent crime); in 2010 just 6% of all sentences were for firearm possession offenses, and by 2023 that had increased to 25%. Conversely, a smaller share of prison sentences involved drug-law violations or property crimes (e.g., theft, burglary). Again, Illinois is a diverse state, but these trends and patterns were evident across most counties.

What explains these shifts in sentencing patterns, so remarkably consistent across Illinois’ diverse communities? There have not been any specific laws passed in the last decade that would account for changes like these. For example, the legalization of cannabis for recreational purposes occurred in 2020 (long after this trend began), and most cannabis offenses were previously classified as misdemeanors and therefore not subject to prison sentences. More plausible explanations are the combination of greater availability of robust community-based options, concerns over the cost of incarceration, and a shift in thinking regarding the goals of sentencing. For example, in many jurisdictions over the past 20 years, treatment alternatives—like specialized treatment courts, jail-based programs, enhanced probation services, and police-led deflection efforts that divert people into treatment rather than further into the justice system—have seen an increase in capacity and acceptance. The state has also dedicated funding to support and incentivize the use of alternatives to incarceration, such as the Adult Redeploy Illinois (ARI) program created in 2010. More broadly, the increased use of probation supervision is likely due to probation departments across Illinois adopting evidence-based practices, which has improved the effectiveness of non-prison sentences in addressing needs and reducing recidivism. Indeed, despite this increased use of probation as a sentence, the rate at which those placed on probation for a felony-level offense had their sentence revoked due to a violation only increased slightly between 2010 and 2023, from 14% to 19%.

Loyola’s Center for Criminal Justice estimates that the reduced likelihood of a prison sentence being imposed has resulted in approximately 37,000 fewer sentences to prison over the 13-year period from 2011 to 2023. On the other hand, the slight increase in the likelihood of probation revocation translated to an estimated 6,500 additional probation sentences being revoked, which likely resulting in additional prison sentences during those same 13 years. Thus, the net impact of these changes on admissions to prison was roughly 30,300 fewer sentences to prison between 2011 and 2023.