United States Department of Justice. Office of Justice Programs. Bureau of Justice Statistics. National Prisoner Statistics, 1978-2012. ICPSR34981-v1. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2014-04-23. https://doi.org/10.3886/ICPSR34981.v1
Persistent URL: https://doi.org/10.3886/ICPSR34981.v1
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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.
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.
Mode of Data Collection:
Extent of Processing: 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.