Philadelphia’s efforts to reform its criminal justice system reached a milestone last month when the city completed 10 years of participating in the MacArthur Foundation Safety and Justice Challenge, an initiative aimed at safely reducing jail populations and rebuilding criminal justice systems.
When Philadelphia joined the national program in 2015, the city’s jail population stood at 8,082. By July 2025, that number had fallen to 3,436 — a nearly 58% decline.
Alyssa Balletta, director of research and development for Philadelphia’s First Judicial Court, said establishing a better data-sharing framework between law enforcement agencies, district courts, public defenders and the Department of Prisons helped cut the city’s jail population in half.
“We had to understand who’s in our [jail] population, so that we could really focus on tailoring our strategies, tracking the efforts and have the ability to course correct,” said Balleta, who led the data infrastructure project.
At the core of Philadelphia’s success was an emphasis on reducing pretrial incarceration, when an individual is held in jail or detention after arrest, but before a conviction or trial, commonly due to an inability to afford bail. Balletta said the criminal justice agencies were very siloed and did not trust each other.
“Back in 2015, people kept their data very close to the chest and didn’t want to share, didn’t want to dive into it openly,” Balletta said. “So we created this really important framework in data sharing to increase transparency around criminal justice data.”
Using data compiled from monthly reports from each participating agency, Balletta built a public webpage that provides an overview of Philadelphia’s jail population each month. The webpage, which links to PDFs containing statistics about the city’s changing prison population, shows that, in 2015, more than 2,000 people were in jail on pretrial status alone, many held on cash bail amounts of $50,000 or less.
“We created this unprecedented snapshot, taking a prison census file that every day we get a transmission from the jail that shows everyone that’s in custody on that day,” Balletta said. “And using the person identifier, we then were able to join it with court data elements to better understand the detainers and holds on an individual.”
The agencies created an early-bail review system for non-violent offenses, such as theft, drug and property charges, setting the threshold at $50,000. Eligible individuals were presented to a judge within five days of their first court appearance and had the potential to see their bail amounts reduced or eliminated.
Balletta said the court’s IT department automated the creation of a list of qualifying individuals who could be connected to services, like home monitoring, mental health or substance abuse counseling — alternatives to detention while awaiting their trials.
“It really made a difference, and really showed how we can get folks comfortable with leveraging data,” Balletta said. “Instead of everyone looking from their perspective of this is what we think we’re seeing, or relying heavily on a lot of anecdotal evidence, we now had tangible data, tangible insight.”
She said the city immediately saw a reduction in its jail population, and in 2019 it increased the threshold of early bail review to $100,000, and then to $250,000 in 2021. The jail population dropped so dramatically that the city was able to close its House of Corrections, the oldest jail in the Philadelphia.
Fewer than 5% of people in custody in Philadelphia’s jails are now held on cash bail at or below that threshold.
“Anytime I talk about data, it’s really all about relationship building and really having transparency and integrity around your data,” Balletta said. “Not everyone feels comfortable with data and it’s an afterthought. But we have to be embedded into every space, because we can really help move the needle when data is involved.”
Written by Sophia Fox-Sowell
Sophia Fox-Sowell reports on artificial intelligence, cybersecurity and government regulation for StateScoop. She was previously a multimedia producer for CNET, where her coverage focused on private sector innovation in food production, climate change and space through podcasts and video content. She earned her bachelor’s in anthropology at Wagner College and master’s in media innovation from Northeastern University.