Note: This research was prompted by questions raised to Dr. David Olson by students at Danville Correctional Center, enrolled in a policy class offered by the University of Illinois Urbana-Champaign’s Education Justice Project .

During the early 1990s, violent crime in the United States reached its highest levels since the Federal Bureau of Investigation started keeping records.

One significant policy response at the federal level was the Violent Crime Control and Law Enforcement Act of 1994—popularly known as the “1994 Crime Bill”—which expanded funding for law enforcement, stiffened federal penalties for violent crimes, banned assault weapons, and made a host of other changes aimed at addressing and reducing violence. One of the most consequential components of the Crime Bill established the Violent Offender Incarceration and Truth-in-Sentencing (VOI/TIS) Incentive Formula Grants Program, which not only provided massive federal funding for new and expanded state prison construction, but set aside much of it for states that toughened up and reformed their criminal sentencing laws by adopting “Truth in Sentencing.”

Truth in Sentencing (TIS) laws

mandate that those sentenced to prison for certain serious crimes actually remain imprisoned for all or a substantial portion of the court-specified sentence, no matter what early release or “good time credit” mechanisms might otherwise be employed to promote good discipline and encourage rehabilitative efforts in prison.

Illinois was one of many states that responded to the new federal funding incentives set up by the Crime Bill, enacting TIS legislation

and eventually receiving a total of $124 million through the VOI/TIS grant program from 1996 through 2001.

Illinois’ original TIS scheme required that 100% of a court-imposed sentence be served following conviction for First Degree Murder, 85% for a range of other serious offenses,

and 85% for specified offenses when they result in great bodily harm.

TIS in Illinois was expanded to cover other offenses in 2005,

2007,

and 2010.

The Legacy of Truth-In-Sentencing in Illinois

The dramatic wave of violent crime that prompted the original 1994 Crime Bill receded long ago,

but the effects of the incentives created by the Crime Bill remain to this day. Many of these lasting effects were documented in a 2009 Loyola University analysis of the first ten years of Truth in Sentencing, which found among other things that TIS had greatly increased the time required to be served in prison under court-imposed sentences but did not have any significant influence on the extent and nature of disciplinary incidents in Illinois’ prisons. In fact, people subject to TIS had patterns of disciplinary infractions similar to those not subject to TIS.

Now a new study conducted by the Center for Criminal Justice at Loyola, analyzing Illinois Department of Corrections (IDOC) data through December 31, 2024, updates and expands on the 2009 report, illuminating the ways that a quarter of a century of TIS has profoundly shaped the current population of Illinois prisons.

TIS and Sentence Lengths

When TIS legislation was first proposed in Illinois, many predicted that the change would not actually result in longer prison stays: as a practical matter, courts would simply take the new limits on sentencing credits into account when calculating what sentence to impose, adjusting the total length of each sentence downward to reflect the fact that more of it would actually be spent in prison.

However, the 2009 Loyola analysis found otherwise: in general, sentences imposed during the first decade of TIS had not in fact been “offset” in this way, and those convicted of offenses subject to TIS were being imprisoned for up to twice as long as a result.

Our updated analysis of IDOC population data through 2024 confirmed the original finding from 2009: reductions in the length of court-imposed sentences for offenses subject to TIS have been minimal, and accordingly lengths of prison stays in TIS cases have dramatically increased. For example, among those sentenced to prison for first degree murder, the average sentence imposed in the years before TIS was 38.3 years, with roughly 50% of that sentence being served; in the period after TIS was implemented--when 100% of the sentence had to be served--the average was 35.5 years, and among those sentenced more recently (between 2021 and 2024) the average was 38.3 years. Similar patterns were found in pre- and post-TIS sentencing in cases of aggravated criminal sexual assault, aggravated discharge of a firearm, and aggravated domestic battery.

Proportion of Prison Population Subject to TIS

The overall proportion of TIS-sentenced individuals in Illinois prisons

has increased steadily over time. While only 16% of those in Illinois prisons on December 31, 2006 were TIS-sentenced, by December 31, 2024 the share of the prison population with TIS sentences had jumped to 51%. (Figure 1)

This dramatic increase was the result of two opposing trends. On one hand, the number of people in prison under sentences not subject to TIS has been decreasing for decades, reflecting both an overall decline in crime and a widespread move away from use of prison as a response to less serious, nonviolent offending. Illinois prisons held 33,451 people serving sentences for non-TIS offenses on December 31, 2006, excluding those in prison on technical violations of their Mandatory Supervised Release (MSR). By December 31, 2024, that number had fallen to 12,989, a 62% decrease.

Over the same period, by contrast, the number serving TIS sentences in Illinois prisons more than doubled, from 6,524 on December 31, 2005 to 13,306 on December 31, 2024. This increase did not reflect trends in serious crime, so much as the relatively longer periods of incarceration for those sentenced for TIS offenses. (Figure 2)

TIS-Sentenced Population Profile

While the number of individuals in IDOC serving a sentence subject to TIS has increased over time, the characteristics of these individuals have remained fairly consistent. For example, throughout the period from 2005 to 2024, 96% of the individuals in IDOC serving sentences subject to TIS were male and 4% were female. Throughout the period, roughly 55% of those subject to TIS in IDOC were Black, 26% were white, and 19% were Hispanic. The one notable change was in the proportion of those sentenced to prison from Cook County: among those in IDOC subject to TIS in 2005 through 2010, roughly 56% had been sentenced in Cook County, but by the end of 2024, the proportion was just under one-half (48%).

Of those serving a sentence for a TIS offense on December 31, 2024, almost one-half (48%) were serving a sentence at 85% for a forcible felony offense that involved great bodily harm and an additional 36% were serving a sentence at 100% for First Degree Murder. (Figure 3) These two categories of TIS offenses were in the original TIS law that became effective in 1998, and collectively those sentenced for those offenses still accounted for 84% of all those serving a TIS sentence on December 31, 2024. The remaining 16% of those serving TIS sentences on that date had been sentenced for offenses that were added to the list of TIS offenses after the original law was passed, mostly “85% offenses” (such as Armed Habitual Criminal, Aggravated Discharge of a Firearm, Aggravated Domestic Battery, Aggravated DUI with bodily harm or death), along with a small number of drug-law violations that require 75% of the sentence to be served.

Extended, Life and “Virtual” Life Sentences Under TIS

Of the 13,200 individuals in IDOC serving TIS sentences on June 30, 2024, almost half—6,300 individuals—would already have been released from prison if not for TIS (that is, if they had instead been eligible for day-for-day good conduct credit).

Only 4% of this TIS group (528 people) had been sentenced to remain in prison for their “natural life.” But another 32% (4,224 people), because of how long they will be required to serve under TIS, are projected to be in prison beyond their 64th birthday (Figure 4). Since research shows that 64 is the average age of all those dying of natural causes in prison,

it is statistically likely that the deaths of this latter group will occur before release; accordingly, they may be thought of as serving “virtual” life sentences.

In the absence of TIS—that is, if all those currently subject to TIS were instead eligible for standard day-for-day good conduct credits—only a total of 11% (1,492 people) would be projected to be incarcerated beyond their natural life expectancy (528 because they are serving natural life sentences and another 924 because their sentences, even given good conduct credits, will keep them in prison beyond their 64th birthdays) (Figure 5).

The Costs of TIS

There is no simple way of calculating the costs of TIS in Illinois, and certainly no way that is universally agreed on. But it is certain that the greatly lengthened prison stays that come with TIS do have costs. In 2014, the IDOC estimated that incarcerating one prisoner for one year in Illinois cost more than $22,000, and more than $37,000 with capital costs, pension contributions, and employee benefits factored in.

More recently the IDOC reported that, for each person in its custody during Fiscal Year 2024, the agency spent more than $49,000.

It's true that many of these costs are fixed, and are not necessarily responsive in the short term to changes in the prison population. But if we simply took all those serving TIS sentences as of June 30, 2024—less those serving life sentences or sentences long enough to exceed their life expectancy even without TIS enhancements—and calculated how much time would be served if they were eligible for day-for-day good time credit, the 11,708 individuals involved would collectively have served 111,487 fewer years in prison. That translates into potential cost savings ranging from about $2.5 billion (using the 22,000 annual cost figure) to about $5.4 billion (using the $49,000 annual cost figure).

Conclusion

The implementation of Truth-in-Sentencing in Illinois was seen as a reform to sentencing policies at a time when the level of violent crime in the U.S. was at a peak, and was incentivized through the provision of significant federal grants to support prison construction. At the time of its passage some suggested it was merely a symbolic change and that the courts would negate any true increase in the amount of time actually served in prison by simply reducing the length of the imposed prisons sentences. In the end, sentence lengths did not change and those sentenced to prison from crimes subject to TIS are spending longer in prison than they were before the offenses were subject to TIS. While Illinois’ prison population has decreased dramatically over the past 15 years, the number of people incarcerated who are subject to TIS has actually increased, and these individuals now account for the majority of individuals serving a sentence in Illinois’ prisons.