ICE Detention Trends Data

Vera’s ICE Detention Trends dashboard reveals an unprecedented level of detail about ICE detention populations, both nationally and in the 1,081 facilities in which ICE detained people, on each day between October 1, 2008, and March 30, 2020—fiscal year (FY) 2009 to mid-FY2020. This repository includes the aggregated data visualized in the dashboard, including information on:

• Midnight population: the daily number of people detained at midnight (nationally and by facility).
• 24-hour population: the number of people detained for any part of a given day, including those whom ICE transferred or booked-out of custody before midnight (nationally and by facility). While ICE relies solely on midnight populations in its reporting, Vera includes both types of daily populations—midnight and 24-hour—as the two can differ drastically.
• Book-ins: the daily number of people ICE booked into custody (nationally).
• Book-outs: the daily number of people ICE booked out of custody (nationally).
• Facility names, locations, and types (as coded by ICE in other datasets).

About the Data

The dashboard primarily draws from ICE detention datasets released through a Freedom of Information Act (FOIA) request, shared with Vera by David Hausman, assistant professor of law, University of California, Berkeley. To overcome limitations of the original data, Vera developed a novel algorithm to construct individual detention histories, from a person's initial book-in to their final-book out, inclusive of any transfers. Doing so allowed Vera to account for duplicated data and compute detention populations. Vera drew from additional ICE datasets for information on facility locations and facility types. Otherwise, Vera chose to present the ICE detention data "as is" to the greatest extent possible, including any inconsistencies or errors that may be present in the data compiled and shared by ICE. For more information about the data and Vera's methodology, see the accompanying technical appendix.

Data Dictionaries

The directory tree below outlines the organization of this repository, followed by data dictionaries for each data file.

ice-detention-trends/
    |-- README.md
    |-- License.md
    |-- national.csv
    |-- facility/
    |   |-- FY2009.csv
    |   |-- FY2010.csv
    |   |-- FY2011.csv
    |   |-- FY2012.csv
    |   |-- FY2013.csv
    |   |-- FY2014.csv
    |   |-- FY2015.csv
    |   |-- FY2016.csv
    |   |-- FY2017.csv
    |   |-- FY2018.csv
    |   |-- FY2019.csv
    |   `-- FY2020.csv
    `-- metadata/
        `-- facilities.csv

national.csv

National population statistics for each day between October 1, 2008, and March 30, 2020, including midnight population, 24-hour population, book-ins, and book-outs.

Variable	Type	Description
date	date	The date for which each metric is reported (yyyy-mm-dd format)
daily_pop	numeric	24-hour population: the number of people detained at any point during a given day, including those booked out before midnight
midnight_pop	numeric	Midnight population: the number of people detained at 11:59pm on a given day
book_in	numeric	Book-ins: the number of people booked into ICE custody
book_out	numeric	Book-outs: the number of people booked out of ICE custody

facility/

FY20XX.csv

Facility-level population statistics for each day between October 1, 2008, and March 30, 2020, including midnight population and 24-hour population. To make file sizes more manageable, Vera split the data into separate .csv files by fiscal year (October 1 of the previous year through September 30 of a given year). FY2020 is a partial fiscal year covering October 1, 2019, to March 30, 2020.

Variable	Type	Description
detention_facility_code	string	The unique identifier used in the ICE detention data for each facility
date	date	The day each count is reported for (yyyy-mm-dd format)
daily_pop	numeric	24-hour population: the number of people detained at any point during a given day, including those booked out before midnight
midnight_pop	numeric	Midnight population: the number of people detained at 11:59pm on a given day

metadata/

facilities.csv

A lookup table mapping each detention_facility_code to information about the facility, drawing from supplemental ICE data and other sources. (See technical appendix for more detail.)

Variable	Type	Description
detention_facility_code	string	The unique identifier used in the ICE detention data for each facility
detention_facility_name	string	The facility name associated with the detention_facility_code in the ICE detention data
type_detailed	string	The facility type as coded by ICE in supplemental data sources
latitude	numeric	The latitude coordinate of the facility location
longitude	numeric	The longitude coordinate of the facility location
city	string	The city in which the facility is located
state	string	The state abbreviation code. This includes codes for U.S. territories (e.g. "PR" for "Puerto Rico")

License

By downloading the data, you hereby agree to all the terms specified in this license: License.md.

Credits

Data analysis: Noelle Smart and Zachary Lawrence Data engineering: Zachary Lawrence Design and development: Jill Hubley Writing: Noelle Smart Editing: Léon Digard

Acknowledgements

Vera thanks David Hausman, assistant professor of law, University of California, Berkeley, for providing the detention-stint-level ICE detention datasets acquired through FOIA requests which are visualized in this dashboard. Vera also thanks the following organizations for making available supplemental ICE datasets Vera used to process the data and geocode facilities: Human Rights Watch, Transactional Records Access Clearinghouse, National Immigrant Justice Center, Immigrant Legal Resource Center, and the Marshall Project.

Vera would like to thank the following colleagues for their support in providing editing, design, and guidance: Nina Siulc, Chris Henrichson, Jasmine Heiss, Jacob Kang-Brown, Kica Matos, Will Snowden, and Lizzie Allen. The authors wish to acknowledge the work of Dennis Kuo, who contributed to the development of the Detention Stay ID algorithm as a former Senior Data Scientist at Vera.

Contact

For more information, contact Noelle Smart, principal research associate, at [email protected].