Pretrial Detention and Supervision Under the PFA

Two years into its implementation, what can we say about the effects of the Pretrial Fairness Act (PFA) on pretrial jail populations in Illinois? Besides doing away with monetary conditions on pretrial release, the PFA severely restricted eligibility for pretrial detention and increased the state’s evidentiary burden in pretrial detention hearings. It would be natural to expect that this would result in fewer people being held in jail pretrial, and the law’s proponents certainly hoped that it would do so. Has it?

In our report on The First Year of the Pretrial Fairness Act, which summarized data available as of September of 2024, we examined changes in the average daily population (ADP) of jails pre- and post-PFA, and found that they had in fact fallen substantially, with monthly average jail populations declining 14% in Cook and other urban counties, and 25% in rural counties. Still, we cautioned that the sharpest drops in ADP had occurred in the first few months of PFA implementation, after which pretrial jail populations appeared to level out, or even rise. There was also considerable variation among counties, with some seeing jail population increases above their pre-PFA levels, even in the first year.

Now that another year has passed, a new analysis of pretrial jail populations in Illinois reveals a more complicated picture. While pretrial jail population numbers as of July 2025 were still down in Illinois as a whole (i.e. when individual county jail populations are added together), they had rebounded considerably since the first few months of the PFA. And much of this rebound was due to pretrial detention increases in Cook County and a few other large counties (e.g., Lake and Kane Counties), where pretrial populations in July 2025 were actually higher than they were before the PFA.

Explaining Jail Population Trends

What accounts for these patterns? Since ADP trends vary by county, explanations must be sought at least in part at the county level. But in general, jail populations are determined by admissions and length of stay. The volume of admissions may be influenced by county-level trends in arrests, in case filings, in the use of citations to appear, and in the rates at which pretrial detention is sought and imposed. (As we reported after the PFA’s first year, both the likelihood of a detention petition being filed and the likelihood of its being granted varied widely across individual counties.) All of these can also change over time within the same county, in response to local conditions, high-profile events, changes in leadership or policy, clarifications or changes in interpretation of what the law requires, and so on.

An additional factor that may be affecting jail admissions, according to practitioners we’ve interviewed around the state in the PFA’s second year, is an increase in individuals being held in jail for violations of pretrial release conditions. The PFA sets an extraordinarily high bar for initial detention decisions, requiring the state to prove by clear and convincing evidence that the defendant poses a danger to the public or a high risk of flight from prosecution, and that no conditions less restrictive than pretrial detention will suffice to mitigate those risks. But no comparable barriers prevent courts from detaining individuals who violate the conditions of their pretrial release. A failure to appear at a required hearing may be sanctioned with a jail term of up to 30 days, for example. And while the PFA does impose additional requirements for a revocation of pretrial release, it’s a much simpler matter for the state to make the minimum showing called for under the law.

Revocation following the violation of a court-imposed condition may be available even in cases where neither the original offense charged nor the violation itself would have been eligible for initial detention, as long as both rise at least to the level of a felony or Class A misdemeanor.

It makes sense that violations of release conditions would accumulate over time, and that system responses to those violations would only begin to impact jail population numbers later on in the PFA implementation period. We are currently exploring what the court data can tell us about release revocations and sanctions for hearing nonattendance, and the extent to which they have contributed to recent increases in jail populations.

Pretrial Supervision Under the PFA

While pretrial jail populations are down in Illinois as a whole (i.e. when all counties are added up) following two years of PFA implementation, the total number of people under some form of pretrial correctional control in Illinois—either in jail custody or under pretrial supervision—has actually risen 17%. Increases in pretrial supervision populations since the PFA went into effect have more than offset declines in jail populations. That’s true statewide, in Cook, and in other urban counties outside of Cook. But it’s especially true in rural Illinois, where the number of defendants under pretrial supervision grew astronomically (138% from July 2023—pre-PFA—to July 2025—post-PFA).

The likely reason for much of this growth, particularly in rural areas, has less to do with the PFA itself than with the creation of the Office of Statewide Pretrial Services (OSPS). OSPS was launched in 2021, began providing bond court investigations in 2022, and began offering state-funded pretrial supervision in 2023. Prior to that time, most counties in Illinois had no pretrial service capacity at all. Except in the larger counties, most judges were unable to order pretrial supervision, and could only choose between ordering release and requiring payment of bond. Now, however, thanks to the establishment and expansion of OSPS, all Illinois judges have the option of ordering pretrial supervision in appropriate cases.

This research is supported by Award No. 15PNIJ-21-GG-02807-RESS awarded by the National Institute of Justice, Office of Justice Programs, U.S. Department of Justice. The opinions, findings, and conclusions or recommendations expressed in this publication are those of the authors and do not necessarily reflect those of the Department of Justice. This research is also generously supported by The MacArthur Foundation and Arnold Ventures.