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Note: this is a public repository for data collected as part of the Jail Data Initiative

Jail Data Initiative(JDI)

NYU Public Safety Lab

The problem of overincarceration has received considerable attention of late. The focus of this attention, however, has largely been on state and federal prison systems. Often overlooked are local jails. In any given year, county jails will see approximately 11 million new admissions, often because defendants lack the funds to post bail, or even because they lack the funds to pay their fines. Yet we know little about county jail practices, including which counties are systematically jailing defendants pre-trial and/or post-fine, and about the consequences of these practices.

It is possible that longer periods of pre-trial detention, or detainees’ delayed access to counsel, actually increase recidivism, and/or escalate petty offending into more serious offending. Through the generous support of Arnold Ventures, the Chan Zuckerberg Initiative, the Pew Charitable Trusts, the Proteus Fund, and NYU's Moore-Sloan Data Science Environment, our data science team is collecting and merging daily county jail rosters and criminal case records in over 1,000 counties.

We began collecting daily detainee-level data in September 2019. As we scrape a jail roster, we simultaneously extract multiple structured data fields, which generally include detainee name, date of birth, gender, race/ethnicity, booking charges, bond/bail status, booking date, and release date. We are also able to identify if and when released detainees are rebooked into the same jail. Because the detainee-level data contain personally identifying information (PII), we are not releasing these data for public access. Researchers interested in working with these data may contact us; see below.

Methodological Notes

  • We are making available daily jail population counts for every facility in the United States from which we are currently receiving daily roster data. We will update these counts as new roster data are collected.
  • Roster URLs are manually verified to ensure that they are reporting official jail roster data in the public record.
  • We are sharing these data with the Vera Institute of Justice to support their work on jail populations.

Contact Information

Please contact Public Safety Lab Director Anna Harvey or Lead Data Scientist Orion Taylor (WHO WE ARE) with questions, comments and feedback.


A repository for publicly accessible data collected as part of the Jail Data Initiative (JDI) by the Public Safety Lab at New York University






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