(Co-authored with Oliver Hinds, Eital Schattner-Elmaleh, and James Wallace-Lee for the Vera Institute of Justice.)

This is the most updated version of a white paper that was first published in 2015. Incarceration Trends, a project of the Vera Institute of Justice, aims to inform the public debate on mass incarceration and help guide change by providing easily accessible information on the number of people in jails and prisons for every county in the United States. One part of the project is a data tool—available at trends.vera.org—that displays publicly available but disparately located data about incarceration in counties and states. This tool can be used for reference and measurement by justice system stakeholders and others looking to understand how their jail and prison is being used and how it compares with other places, and to spot problem areas—such as excessive growth or racial or ethnic disparities. Currently, the Incarceration Trends tool displays jail data for every county with a jail, and prison data up to 2016 for all counties in 33 states: Alabama, Arizona, California, Colorado, Florida, Georgia, Indiana, Iowa, Kentucky, Maine, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Nebraska, Nevada, New Hampshire, New Jersey, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Washington, Wisconsin, and Wyoming.

To support further research on incarceration, Vera has released a complete dataset that backs the Incarceration Trends data tool. The data set is available as a county based file as well as a more detailed jail jurisdiction based file from Vera’s github.

The purpose of this document is to provide detail on the sources and methods used to compile the jail dataset. The first analysis using this dataset can be found in In Our Own Backyard: Confronting Growth and Disparities in American Jails (Subramanian, Henrichson, and Kang-Brown, 2015).

One note is that jail data for the five boroughs of NYC are stored under the record for Manhattan, county fips code = 36061.

Recommended citation: Kang-Brown, J., O. Hinds, E. Schattner-Elmaleh, J. Wallace-Lee. “Incarceration Trends Project: Data and Methods for Historical Jail Populations, 1970-2018,” Vera Institute of Justice, September 2020.

(See also a white paper on localizing prison data, co-authored with Oliver Hinds, Olive Lu, and James Wallace-Lee for the Vera Institute of Justice.)

Understanding how counties in the United States use incarceration is crucial for developing criminal justice policy and for driving reform. Previously, we assembled a dataset containing jail incarceration information at the county level for the years 1970-2015. Here, we aim to compile information about how counties contribute to state prison populations. Toward this goal, we used data made available by the Bureau of Justice Statistics (BJS) through the National Corrections Reporting Program (NCRP), which contains individual state prison admission and release records for the years 1983-1999, and individual prison term records for the years 2000-2016. Since records in the NCRP data include county of commitment, we were able to aggregate records to estimate prison admissions and population at the county level. We supplemented data from the NCRP with data from state corrections department reports when the NCRP data was missing or corrupt. We validated our estimates by summing data across all counties in a state, then comparing these with state-level prison admissions and population data available through the BJS National Prisoner Statistics Program. Through this comparison process and other validation approaches, we identified several challenges that impede accurate estimation of county-level statistics using the NCRP data. The result of our efforts is a novel U.S. county-level dataset of prison population and admissions counts from 1983-2016.

Recommended citation: Hinds, O., O. Lu, J. Wallace-Lee, J. Kang-Brown,“Reconstructing How Counties Contribute to State Prisons,” Vera Institute of Justice, January 2020.