National Prisoner Statistics, [United States], 1978-2020 (ICPSR 38249)
Version Date: Dec 16, 2021 View help for published
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The National Prisoner Statistics (NPS) data collection began in 1926 in response to a congressional mandate to gather information on persons incarcerated in state and federal prisons. Originally under the auspices of the U.S. Census Bureau, the collection moved to the Bureau of Prisons in 1950, and then in 1971 to the National Criminal Justice Information and Statistics Service, the precursor to the Bureau of Justice Statistics (BJS) which was established in 1979. From 1979 to 2013, the Census Bureau was the NPS data collection agent. In 2014, the collection was competitively bid in conjunction with the National Corrections Reporting Program (NCRP), since many of the respondents for NPS and NCRP are the same. The contract was awarded to Abt Associates, Inc.
The NPS is administered to 51 respondents. Before 2001, the District of Columbia was also a respondent, but responsibility for housing the District of Columbia's sentenced prisoners was transferred to the Federal Bureau of Prisons, and by yearend 2001 the District of Columbia no longer operated a prison system.
The NPS provides an enumeration of persons in state and federal prisons and collects data on key characteristics of the nation's prison population. NPS has been adapted over time to keep pace with the changing information needs of the public, researchers, and federal, state, and local governments.
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Three distinct collections comprise the NPS:
The NPS-1 is an annual collection known as the "Summary of Sentenced Population Movement." Before 1978, the collection tracked admissions and releases by type and sex during each calendar year, as well as the number of prisoners in custody by sex and sentence length on December 31.
In 1978, NPS-1 was expanded to include the number of prisoners under the jurisdiction of state and federal adult correctional officials, the number of inmates held in local jails solely to ease overcrowding in prisons, and the race and Hispanic origin by sex of the jurisdiction population at yearend.
In 1991, NPS-1 was further expanded to include questions on the number of human immunodeficiency virus (HIV) infections and confirmed acquired immune deficiency syndrome (AIDS) cases in the custody population. Note: HIV/AIDS data for 2016-2020 have not yet been released by BJS.
In 1999, the NPS-1 was expanded again to collect data on inmates housed in local facilities without reference to prison overcrowding, inmates held in other state or federal facilities, and inmates held in privately operated facilities. In addition, the race and Hispanic origin questions were combined into a single item to better comport with administrative recordkeeping systems maintained by state departments of correction (DOCs). Finally, the survey began collecting more detailed counts of inmate deaths by cause.
The NPS-1A was introduced in 1981 to track the rapidly growing prison population. It included counts of the number of inmates under jurisdiction and in custody of prisons, by sentence length and sex, on June 30 of each year. This collection was eliminated in 2010 to reduce burden on data respondents.
The NPS-1B was added to provide advance counts of the December 31 (yearend) populations and to obtain data by sex, race, and sentence length. It was expanded in 1982 to include counts of inmates housed in local jails because of prison overcrowding, and again in 1983 to provide measures of housing capacity and numbers of early releases due to prison overcrowding.
NPS-1 and NPS-1B were merged in 2007 under the title NPS-1B "Summary of Sentenced Population Movement." This single collection captures counts by sex of yearend jurisdiction and custody populations by sentence length; number of prisoners held in local, federal, private, and other state facilities; the race and ethnicity of inmates; types of admissions and releases during the calendar year; prison system capacity; and HIV infections and confirmed cases of AIDS. In 2011, two items were added from the former NPS-1A collection, including the yearend custody counts of noncitizens and inmates age 17 or younger.
The NPS datasets archived here draw from the NPS-1 collection until 2007, when the data were consolidated in the NPS-1B. The counts of noncitizens and persons age 17 or younger have been retained from the NPS-1A.
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Prisoners under jurisdiction of federal or state correctional authorities in the United States from 1978 to 2020.
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2021-12-16 ICPSR data undergo a confidentiality review and are altered when necessary to limit the risk of disclosure. ICPSR also routinely creates ready-to-go data files along with setups in the major statistical software formats as well as standard codebooks to accompany the data. In addition to these procedures, ICPSR performed the following processing steps for this data collection:
- Created variable labels and/or value labels.
- Standardized missing values.
- Performed recodes and/or calculated derived variables.
- Checked for undocumented or out-of-range codes.
The public-use data files in this collection are available for access by the general public. Access does not require affiliation with an ICPSR member institution.