A Look Back at MacArthur’s Big Bet to Reduce Jail Populations

With almost 2 million people behind bars at any given time, the U.S. incarcerates more people than any other country in the world. And while philanthropic funders have backed a number of efforts to reform prisons, jails have received far less attention.

According to the most recent data from the Bureau of Justice Statistics, there were approximately 660,000 people being held in jail in the U.S. in mid-2024, with around 7.9 million people cycling through the jail system annually. In theory, jails should be short-term facilities that hold individuals awaiting trial (who have not been convicted of a crime) and who are deemed to be flight risks or a danger to the community, or holding individuals serving sentences of a year or less. 

In reality, though, more than 60% of people in jail are there because they cannot afford to pay cash bail. Jails are also used to hold people who are suffering from mental health  and substance abuse issues, as well as those who are unhoused. This overreliance on jails reflects many of the systemic issues that plague the nation, including poverty, structural racism, insufficient mental healthcare and a lack of affordable housing. 

The MacArthur Foundation has spent the past decade looking to change the nation’s relationship with jails. In 2015, MacArthur launched its Safety and Justice Challenge (SJC), a 10-year initiative that sought to both safely reduce jail populations and transform the way the country thinks about jails and how they’re used.

Through SJC, the foundation committed $411 million across 525 grants to 171 organizations in an effort to help cities and counties improve their local criminal justice systems and make their communities safer. In total, 100 cities and counties across 36 states participated in the Safety and Justice Challenge. 

SJC was one of MacArthur’s “Big Bets,” which were time-limited initiatives to create transformative change in different fields, including climate solutions, nuclear challenges and criminal justice. MacArthur began winding down its “Big Bets” in 2020. Its final initiative — climate solutions — will end this year.

Starting local — and centering racial equity

According to MacArthur Foundation President John Palfrey, SJC came about when the foundation was developing its criminal justice program strategy. MacArthur wanted to build on its Juvenile Justice program, while also addressing local criminal justice systems. 

“America’s local jails are often people’s first contact with the criminal justice system, with 19 times more annual admissions than America’s prisons. To address overincarceration, we need to start with local jails and the systems that fill them,” Palfrey said. 

A crucial part of this work included addressing — and eliminating — the racial inequities within the justice system. Black people make up a disproportionate percentage of the jail population in the U.S., and on average, stay in jail longer than white people. As part of its work, SJC selected four jurisdictions — Cook County (IL), New Orleans (LA), Philadelphia (PA) and Pima County (AZ) to join a Racial Equity Cohort, which received funding for training and technical assistance focused on racial equity. 

Overall, MacArthur was intentional in trying to include a cross representation of the U.S. Participating communities included large communities like Chicago, smaller communities in South Dakota and Sioux Falls and Rapid City, and midsized locations like New Orleans or Tucson, Arizona.

Over the course of the 10-year period, SJC communities employed numerous reform strategies, including jail population review teams, having public defenders at initial hearings, programs that divert people from jails while also connecting them with support, and programs to address behavioral health needs within the justice system.

A data-driven approach to reducing jail populations

Through SJC, MacArthur aimed to help jurisdictions find solutions that are both data driven and community informed. “We always wanted us to be data driven to help support communities to build up their data infrastructure to really analyze who’s coming into the jail, why they’re coming into the jail, and… think about other ways to get them out of jail more quickly or to have them not even involved in the criminal justice system at all,” said Bria Gillum, senior program officer on MacArthur’s criminal justice team, who added that some individuals being held in jails may be better served by other services and sectors that can provide appropriate assistance.  

SJC’s main data partner was the CUNY Institute for State and Local Governance. The institute developed a set of measures across a subset of criminal justice indicators, such as how people are arrested or brought into the system, how they are processed, whether they have bail hearings, and the outcomes when re-entering society after serving jail time. 

Some participating communities used grant funds to hire new staff to conduct data analysis. SJC also supported training staff within criminal justice agencies or departments, Gillum said. She added that the granular data collected by communities helped both MacArthur and the communities themselves better understand how the U.S. criminal system operates.

Community-led work helps highlight the social determinants of incarceration

Another key aspect of SJC’s work was its community-led approach. Throughout, to find solutions to overincarceration, SJC sought to bring together a variety of community stakeholders, including judges, prosecutors, public defenders, law enforcement, policymakers, victims of crime and formerly incarcerated individuals. 

“People who’ve been impacted by the system are really the ones who have first-hand knowledge of how the system operates [and] what recommendations really need to be put into place to make sure that the same mistakes that we’ve been seeing for decades don’t happen again,” Gillum said. 

One such voice brought in to guide the work as a member of SJC’s advisory council was Xavier McElrath-Bey, executive director of the Campaign for the Fair Sentencing of Youth.

Like other advisory council members, McElrath-Bey participated in quarterly meetings to provide input on SJC’s milestones, help share the priorities of the work’s future, engage in discussions about systemic racism, offer insights into refining SJC’s work, and add nuance. McElrath-Bey described the conversations as “very in-depth and quite soul-searching.”

He noted that bringing system stakeholders together with community members to look closely at the social determinants of incarceration makes it clear that there are ways to “deter and deflect people from the system.” 

“Looking back upon my experience, I know very intimately that the majority of those crimes were crimes of survival. When I was nine years old and I stole from a grocery store, it’s because I was hungry. When I was arrested numerous times for breaking and entering and trespassing into abandoned buildings, it’s because I needed a place to sleep,” McElrath-Bey said. 

He added that even when he committed more serious offenses, more often than not, they were driven by a need for love, belonging and a sense of safety that a gang offered. 

For McElrath-Bey, a more just and fair justice system would look closely at individuals, their experiences, and the inadequacies and deficits they’ve faced. Reformers argue it’s critical to both address the determinants of incarceration while also supporting the determinants of success — education, employment, housing stability and mental health services — all of which help to prevent recidivism and to prevent others from committing crimes in the first place. For SJC, this manifested in part as a prerogative to help jurisdictions reduce the number of people they hold in jail.

Reducing the jail population in Chicago

These broad principles can be seen at work in SJC’s participating jurisdictions, including Chicago, where the MacArthur Foundation is based, and extending to greater Cook County. The county received four separate grant awards totaling $6 million in SJC funding.

In 2015, when the challenge began, Cook County’s jail population was somewhere between 8,000 and 9,000 on average. Over the course of the 10-year challenge, the county’s jail population dropped significantly. By the end of 2025, a total of 6,744 people of all genders were either in jail or community corrections. On average, the Cook County jail population dropped by 30% over the course of the initiative.

Cook County has five separately elected officials who occupy key leadership roles in its justice system — the chief judge, sheriff, state’s attorney, public defender, and the clerk of the court. According to Cook County Board of Commissioners President Toni Preckwinkle, these officials traditionally operated in silos and it was difficult to get people to work together. 

“One of the biggest issues with the criminal legal system is that there’s a lot of cooks in the kitchen,” said Sharone R. Mitchell, Jr., Cook County public defender. “And oftentimes, we… on the outside can say, ‘Hey, this is where I want the system to go,’ but because we rely on so many different people to do so many different things, it’s impossible to get that implemented quickly or easily.” 

The Safety and Justice Challenge, Mitchell said, gave the county’s stakeholders the opportunity to come together, create shared goals and work to reach them. 

At the suggestion of Justice Anne M. Burke, who was the head of the county’s Justice Advisory Council, they engaged the Illinois Supreme Court and asked it to look at bond court as a way of addressing overincarceration, particularly that of Black men, Preckwinkle said. In 2017, the county implemented bond reform, which allowed the release of people who didn’t pose a flight risk or a risk to themselves or the community while awaiting trial. 

“With cash bond, of course, your liberty is contingent on the size of your wallet. So this reform, which dramatically reduced reliance on cash bond, was really helpful in reducing the jail population,” Preckwinkle said. 

Another major change that took place during the challenge was the county’s implementation of an automated court reminder system. Just as people receive appointment reminders from their doctor’s offices, people would receive a phone call — now a text message — reminding them to go to court. 

Other steps the county took include creating a team to review individuals’ cases to identify and address barriers and systemic challenges, and investing in diversion programs. This includes SEED, a 13-month pre-plea deferred prosecution program for individuals aged 18 to 26 years old who have been charged with delivery or intent to deliver. SEED provides education services, cognitive behavior therapy and job training and placement. Once they successfully complete the SEED program, the charges are dismissed. 

Recent data from Cook County shows “a significant drop in homicides” in 2025, falling by more than 30% compared to 2024 and more than 50% since their peak in 2021. Although the rate of violent crime in Chicago, particularly homicides, remains higher than in many other major cities and will always fluctuate on a neighborhood-by-neighborhood basis, the substantial drop is one indicator that the practices the county has implemented are helping — or at the very least aren’t harming — public safety.  

The work to reduce the jail population in Cook County, however, is far from over. “We’ve addressed the challenge of overdetention of individuals accused of nonviolent crimes. That part’s done pretty well, but there are still tremendous racial disparities in the jail population, and that’s a function of endemic racism in the society,” Preckwinkle said. “It’s a little harder for us to address than doing things like eliminating cash bond and sending reminder texts to people.”

“Tough-on-crime” policies and looking to the future

The past few years have seen a return to “tough-on-crime” policies and rhetoric in some parts of the country, fueling overincarceration and cutting against the MacArthur Foundation’s goals with SJC.

“The reality of the situation is that tough-on-crime policies make [public safety] less likely. They destabilize communities. They make people poor. They take away options for people, and when people don’t have options, they do things that we don’t like,” Mitchell said. “I think that there is both a public safety case — a purely public-safety, law-and-order case for these reforms — and then there’s obviously the idea that we want to be fair to people.”

One of the things the criminal legal system needs in this hyper-politicized climate, Mitchell said, is to be able to communicate and defend its successes in making communities safer. “Oftentimes, criminal justice, especially in the current environment, is a communications game. You have a set of actors that are incentivized to scare people or trick people into believing that reform and safety aren’t possible to achieve together, and have taken the opportunity to scare the public into thinking that reducing the jail population comes at a cost for safety.”

So was SJC a successful bet? On one hand, it’s hard to say for certain. Much has happened in the criminal justice space in the decade-plus since MacArthur rolled out the program, including tidal waves of public support for justice reform circa 2020 and the backlash that followed. Some voices, especially on the right, have criticized MacArthur’s decarceration focus, reflecting shifts in the national climate since a pre-2020 era when some in the philanthrosphere saw jail and prison reform as a potentially cross-ideological priority.

Sustaining local buy-in for SJC wasn’t always smooth sailing. Take the case of San Francisco, which joined the SJC network in 2018. Despite initial success in keeping the number of people in the city’s jails at a specific target, the jail population rose over a 17-month period between 2023 and 2024, returning to the same number of incarcerated people as when the initial grant was awarded. That followed the replacement of progressive prosecutor Chesa Boudin, who was recalled in mid-2022, with Brooke Jenkins as the city’s DA.

The DA’s office, which was the agency that led the SJC work in San Francisco, appeared to have had a rift not just with MacArthur, but with Michael Moritz and Harriet Heyman’s Crankstart, which was also supporting restorative justice work in the city. The rift with MacArthur began less than a year after Jenkins took over as DA. IP’s Dawn Wolfe was left with more questions than compelling answers about the DA’s issues with MacArthur — one might point to shifting political winds, but Jenkins’ office initially renewed and lauded its SJC support before turning against the foundation, citing a list of complaints with how MacArthur administered the grant after the foundation withheld a payment “until measurable progress is made” on the grant’s benchmarks. By the end of the initiative, San Francisco’s jail population increased by 8%, and it should be noted that this wasn’t the only SJC network jurisdiction that saw an increase in the number of people incarcerated in its jails.

Overall, though, MacArthur stands by its record on SJC. Throughout its 10-year span, the initiative was able to accomplish much of what it set out to do: It successfully helped foster an overall reduction in jail populations across communities and jurisdictions in the U.S., and it helped move some local justice practices in a fairer direction. But as SJC comes to an end, there’s still a lot of work to do, especially when it comes to eliminating entrenched racial discrepancies in jail populations.

Gillum said that she’s proud to see that there are many funders working on criminal justice reform, ranging from smaller family foundations to large national ones.

She added, “We’re really proud of the work that we’ve done over this 10-year-plus commitment. We’re really excited to see that momentum going forward, and I think overall, we’re seeing crime trends trending downward in most places, and I think part of that can be attributed to some of the work of the SJC. I’m hopeful that the momentum that we were able to support over the last 10 years will continue on for decades to come.”