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Timely jail data can be a guiding light for the criminal justice system

FILE - In this Nov. 1, 2016, file photo, detainees wait in a cell for an appearance in Sacramento County Superior Court in Sacramento, Calif. (AP Photo/Rich Pedroncelli, File)

In a recent opinion piece published in The Hill, director of the Bureau of Justice Statistics (BJS) Alexis Piquero joined with National Institute of Justice director Nancy La Vigne in calling for more reliable data and research on crime. While their article focused on using research evidence and crime statistics to guide violence reduction efforts, there is also a critical need to improve the quality and timeliness of data in other areas of the justice system, including for the nation’s roughly 3,000 local jails.

Why does this matter? Because over the past decade, there was an average of over 700,000 people in jail, with 1 in 6 facilities over 100 percent of their capacity. This overcapacity means that as currently collected and disseminated, BJS data is not timely enough for public officials to make informed decisions about how to deal with issues like jail overcrowding.  

For example, by the time the BJS released a report showing that jail populations had dropped 25 percent at the beginning of the pandemic, that trend had been largely reversed. The most recent report — released in December — showed that, by midyear 2021, jail populations were back to 90 percent of their pre-pandemic levels.

Current national reports only provide limited data on who is in jail, for how long and why. And most data is collected for a single day — the last weekday in June — typically from a sample of less than a third of the nation’s facilities. This makes answering even basic questions difficult — including whether jail populations are rising because admissions are going up, people are staying longer, or both. 

The survey doesn’t ask jails to report admissions by age, race or ethnicity. Information on what people have been charged with is limited to whether the offense was a felony or misdemeanor, with no data available on charge categories, such as the numbers held on violent, property or drug charges. Nationally, jails cost local governments over $25 billion, yet we don’t know how much of these costs are being incurred to put someone in jail for missed court dates or traffic offenses versus serious violent crimes. And we have no information at a national level on what bail is being set for each of these charges.


One reason for this lack of robust, up-to-date information is antiquated data collection. We have seen improvements in timely data reporting in other areas: The Bureau of Labor Statistics produces monthly reports on employment and job openings, and the Centers for Disease Control and Prevention launched a system to help coordinate the daily collection of data on COVID-19 virus levels in wastewater throughout the country. However, when it comes to information on holding people in jails, we rely on limited data that’s 18 months behind.

In his year-end remarks, BJS director Piquero indicated that one of his top priorities is modernization. Recognizing that there is only so much data that can be collected by an annual survey sent to busy jail administrators, we believe modernizing and automating the collection of jail data is critical to improving its quality and utility.

Fortunately, there is now proof that this can be done. In 2021, the Jail Data Initiative (JDI) — a project of New York University’s Public Safety Lab — formally launched a data dashboard that provides insights into who is in over a third of our nation’s local jails, for how long and why. This free dashboard provides state and national trends and individual jail profiles. 

Care to learn how many people were in one of the JDI jails for more than 60 days? How about the share of all admissions in December 2022 that were Black women? JDI’s dashboard can filter data to provide these answers and many more. While the data depends on what is shared in the online jail rosters used by JDI, many facilities include specific charge data, which JDI presents in easy-to-understand charts and tables.

The Pew Charitable Trusts — along with Arnold Ventures and the Chan Zuckerberg Initiative — welcomed the opportunity to support the development of JDI and thereby help public officials make data-driven decisions. While we anticipate that JDI will continue into the near future, we believe that in the long run, collecting and publishing clear and meaningful data on jails is best sustained through government support. JDI has built an impressive and accessible tool using publicly available online rosters, but BJS — by working with jails to get their electronic information directly — could provide a more complete set of jail data. While some jails may not currently upload data to a central location, as of now there are already more facilities in JDI than in the sample for the BJS Annual Survey of Jails.

Over the past decade, there have been, on average, roughly 10 million jail admissions annually. People in jail — 7 in 10 of whom have not been convicted — may be held in crowded facilities for weeks or months, where they not only face exposure to COVID-19 and other diseases but also may be unable to meet their work and family obligations, putting them at risk of losing their jobs or custody of their children. Without current and detailed data, policymakers can’t make decisions that could safely reduce jail populations while lowering the costs to individuals and their communities.

We hope that JDI will help serve as a blueprint for modernizing national jail data. Given the technological tools currently at our disposal and what’s at stake, we all can and should do better.

Julie Wertheimer is a project director and Tracy Velázquez is a senior manager for The Pew Charitable Trusts’ public safety performance and mental health and justice partnerships projects.