National Prisoner Statistics, [United States], 1978-2023 (ICPSR 39657)

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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 2022 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. This expanded collection of deaths in prison by cause was suspended in 2007 after BJS decided to continue collecting prison mortality information through the Mortality in Correctional Institutions program (formerly the Deaths in Custody Reporting Program).

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.

NPS definitions

NPS items and definitions have been adapted over time to reflect the need and changing nature of corrections.

Sentenced prison population

From its beginning, NPS has attempted to collect data on inmates in state and federal prisons who committed serious crimes, although through its original definition, all adult offenders, regardless of the severity of the crime, were included.

• In 1940, a sentence length requirement was imposed to try to obtain counts of felons as opposed to misdemeanants. Only inmates with a maximum sentence of 6 months or more were included in the definition of sentenced prisoners for NPS.
• In 1971, the definition of a felony sentence was changed and standardized across jurisdictions to be a maximum sentence of more than one year.

The NPS-1B currently asks for custody and jurisdiction counts of all prisoners, including unsentenced inmates, inmates sentenced to one year or less, and inmates sentenced to a maximum of more than one year in prison. The term "sentenced" prison population refers to those inmates sentenced to a maximum of more than one year.

Custody versus jurisdiction

Between 1926 and 1976, the official measure of the prison population was the number of inmates in the custody of state or federal correctional officials. State and federal reporting officials were instructed to count all prisoners physically housed under their authority, regardless of whether they or some other entity had legal authority over the inmates.

As states and the Federal Bureau of Prisons increased their use of local jails and interstate compacts to house inmates, NPS began asking states to report a count of inmates under the jurisdiction or legal authority of state and federal adult correctional officials in addition to their custody counts.

Since 1977, the jurisdiction count has been the preferred measure. This count includes all state and federal inmates held in a public or private prison (custody) and those held in jail facilities either physically located inside or outside of the state of legal responsibility, and other inmates who may be temporarily out to court or in transit from the jurisdiction of legal authority to the custody of a confinement facility outside that jurisdiction.

The difference between the total custody count and the jurisdiction count was small (approximately 7,000) when both were first collected in 1977. As more states began to report jurisdiction counts and more states began to rely on local and privately operated facilities to house inmates, the difference increased.

Race and Hispanic origin

NPS started collecting data on race and Hispanic origin in 1978; however, the reporting of the data changed over time. While all states could report on the racial distribution of their inmates, Hispanic origin was reported as unknown for nearly a third of all inmates as late as 1984. In some states this high level of non-reporting was the result of collecting Hispanic origin separately from race, when the prisoner records combined them in a single field. In other states, the prison system did not collect data on Hispanic origin at all, or collected them as a separate racial classification.

In 1997, the Office of Management and Budget published new regulations for the classification, collection, and presentation of federal statistical data on race and ethnicity (https://www.govinfo.gov/content/pkg/FR-1997-10-30/pdf/97-28653.pdf) to better enumerate persons of Hispanic or Latino origin, multiple races, and more specific racial categories. While federal agencies had until January 1, 2003, to comply with the new standards, non-federal entities, including state DOCs, were not bound by the regulations. Most state DOCs have adopted the federal guidelines, although some still cannot meet the regulation due to older information systems that do not record race and Hispanic origin in the standard format.

The determination of race and Hispanic origin differs across states. In some states' DOCs, inmates are asked to self-identify race and ethnicity at time of admission, some rely on information in the arrest or court documents accompanying the prisoner at admission; in others prison officials classify the inmates visually upon entrance to the facility. Based on comparisons of race and ethnicity data recorded on administrative records from the NPS and inmate self-identification data obtained from inmate surveys, Hispanic inmates and inmates identifying as more than one race are underrepresented in the NPS. BJS uses the inmate surveys to adjust for the NPS undercount in its annual Prisoners reports (https://bjs.ojp.gov/data-collection/national-prisoner-statistics-nps#4-0). NPS race and ethnicity data available to the public at the National Archive of Criminal Justice Data (NACJD) are the unadjusted counts originally reported by the states.

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Prisoners under jurisdiction of federal or state correctional authorities in the United States from 1978 to 2023.

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2026-04-02

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