New Report on Jails Shows Lengths of Stay Increasing Across the Country, Even as Admissions Decline

New Report on Jails Shows Lengths of Stay Increasing Across the Country, Even as Admissions Decline

New Report on Jails Shows Lengths of Stay Increasing Across the Country, Even as Admissions Decline

A new report from Data Collaborative for Justice finds higher bail amounts associated with longer lengths of stay, with Black individuals disproportionately affected

New York —  Significant declines in the number of people admitted to jail across a five year period in three different county jails has not produced a proportionate reduction in the number of people in jail on an average day, according to a new report from the Research Network on Misdemeanor Justice (“Research Network”), a project of the Data Collaborative for Justice (DCJ) at John Jay College. This new research examines trends in three U.S. counties — Durham County, NC, Louisville-Jefferson County, KY and St. Louis County, MO — and finds that lower jail admissions across all three sites did not result in commensurate declines in average daily populations within those jails, due largely to increases in average number of days people stayed in jail. Black individuals were consistently overrepresented in jail admissions and stayed longer in jail compared to white individuals.

The report outlines three notable trends:

  • Average length of stay increased over this time period by 18% in Louisville, 24% in Durham, and 20% in St. Louis, which translates to individuals spending between 3.6 and 4.6 days longer in jail in 2019 compared to 2014.
    • The increase in the average length of stay appears to be driven primarily by three factors:
      • Bail continues to be a key driver of jail populations. Average length of stay for individuals with bail set above $5,000 increased between 31% to 54% in all counties
      • Younger people (ages 18-24) are staying in jails longer. In all counties, average length of stay for adults increased to the greatest extent for the youngest group.
      • People admitted to jails on more serious charges are staying longer. In two of three counties, the average length of stay for violent felonies increased by 23 or more days. In all counties, individuals admitted for a violent felony spent on average over 100 days in jail in 2019.


  • Black individuals were consistently overrepresented in the number of admissions and percent of occupied bed days.
    • In 2019, in Louisville, Black individuals made up 24% of the county population but represented 39% of the jail admissions and 49% of bed days. In Durham, Black individuals made up 37% of the county population and represented 69% of jail admissions and 78% of bed days.  In St. Louis, Black individuals made up 25% of the county population, but 55% of admissions and 67% of bed days. 
    • In all counties, Black individuals stayed between 3.3 and 12.1 days longer in jail on average than white individuals.
    • From 2014-2019, Black individuals also saw larger increases in average length of stay than white individuals in Louisville (21%) and St. Louis (34%).


  • In all three counties, jail admissions decreased by about a quarter from 2014-2019, but the average daily population declines were not as substantial because of the increase in how long people remained in the jails over that same period.
    • Admissions dropped 22% in Louisville, 25% in Durham, and 28% in St. Louis. These admissions reductions exceeded the 1%, 19%, and 24% respective declines in ADP, due to the length of stay trends identified above.
    • In all three counties admissions fell for property, drug, traffic, person, and society charges, with admissions cut in half for drug charges in Durham and traffic offenses in Louisville.
    • Throughout the study period admissions for felony charges fell in all three counties, with misdemeanors and violations seeing the largest declines. However, admissions on warrants rose in all three counties.


Understanding Trends in Jail Populations, 2014 to 2019: A Multi-Site Analysis draws on three individual reports from St. Louis, Missouri, Durham, North Carolina, and Louisville, Kentucky. The research finds that, even as admissions declined steadily between 2014 and 2019, (28% in St. Louis, 25% in Durham, 22% in Louisville) the average length of stay steadily increased by more than three days in all counties across the study period. Additionally, in all three counties, 40% or more of people released ended up being readmitted to jail two or more times during the study period.

“These findings, from data across three geographically diverse sites, is a stark indication that efforts to reduce the number of people in jails are being significantly limited by these increasing lengths of stay.” said Melanie Close, Research Associate at the Data Collaborative for Justice. “However, this data represents real progress toward identifying the root causes of these trends and underscores the need for more comprehensive research to better understand the factors contributing to our jail populations.” 

The research conducted in these three counties sheds light on trends around the country and signals that lengths of stay are blunting efforts to reduce jail populations, at a time when the Omicron variant of the COVID-19 pandemic is raising new public health concerns for jails, amidst continued struggles with the Delta variant.  Many jurisdictions continue to face case backlogs due to COVID-related court closures, which are adding to average lengths of stays. While attempts at reforming the criminal justice system often aim to curb jail populations through reductions in arrests and pretrial detention, this research suggests that such efforts may be offset by other factors, such as prohibitive bail costs, that increase the amount of time people are detained.  A close examination of increased lengths of stay has the potential to provide insight into broader jail trends, such as the utilization of jail resources, readmission, and COVID-19’s impact on jails across the country.

Notably, the report finds that Black individuals on average spend longer in jails than white individuals. The magnitude of this disparity differs by county. In 2014, Black individuals spent 4.5 days longer in jail on average than white individuals in Durham and St. Louis, and 9.2 days longer on average than white individuals in Louisville. Furthermore, although the disparity in admissions declined slightly across the study period, racial disparity in average length of stay increased in two counties. In 2019, Black individuals on average spent 3.3 days longer in jail in Durham, 12.1 days longer in jail in Louisville, and 11.6 days longer in jail in St. Louis compared to white individuals.

“This analysis helps us to see the bigger picture of how lengths of stays, the ripple effects of overcrowding in state prisons that delays our ability to transfer inmates after their sentencing, and other factors impact trends in Louisville’s jail population. Before COVID-19, we were already working hard to reduce strain on the system and the pandemic has further illustrated the danger of jail overcrowding,” said Dwyane Clark, Director of Louisville Metro Department of Corrections. “Research partnerships like this will help ensure that future improvements to our justice system are backed by data, not anecdote. And one thing is clear from today’s report: we need more research and data to help us chart a path forward.”

“This research goes a long way toward improving our understanding of the criminal justice system here in Durham,” said Lorraine Taylor, Executive Director of the Juvenile Justice Institute at North Carolina Central University and a lead author of the report. “Partnerships such as these provide us with the vital information needed to ensure we have a holistic understanding of the forces shaping jail populations in our county, and across the nation.”

“As we continue to prioritize the health and safety of all St. Louis residents, it is critical that we utilize all tools at our disposal to better understand the issues facing our communities. With the research included in this report, we are provided with a big picture perspective on where we are improving, and where we can make better decisions in order to effectively allocate resources and advance public safety, justice, and equity,” said St. Louis County Executive, Dr. Sam Page. “While this report shows that we have made significant progress in reducing our jail admissions, it highlights the need for further examination of the systems in place in order to determine the many contributing factors of higher jail populations.

The report was made possible through the support of the Pew Charitable Trusts and can be viewed on Data Collaborative for Justice’s website.


About the Data Collaborative for Justice (DCJ): DCJ leads critical research about frequent interactions between community members and the criminal justice system and aims to ensure that communities, and the governments that serve them, have the necessary information to develop and implement evidence-based policies, practices, and programs. DCJ’s work has informed policy reforms, facilitated partnerships between researchers and government agencies across the country, spurred new scholarly research on lower-level enforcement, and been cited extensively in the press. More information about the Data Collaborative for Justice’s work is available at:

About the Research Network on Misdemeanor Justice: In 2016, DCJ launched The Research Network on Misdemeanor Justice to study lower-level enforcement actions, which represent the most common interactions between communities and the criminal legal system. The Research Network is comprised of researcher-practitioner partnerships in seven jurisdictions committed to producing data, research, and scholarly work on lower-level enforcement trends: Durham, NC; Los Angeles, CA; Louisville, KY; New York City, NY; Prince George’s County; MD; Seattle, WA; and St. Louis, MO. The Research Network seeks to inform criminal justice system operations and policy at the local and state levels. It also seeks to support a national discourse, informed by data, on the role of lower-level enforcement in public safety, trust in the criminal legal system, racial justice, and efficient use of finite taxpayer dollars.