BJS: Bureau of Justice Statistics

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Bureau of Justice Statistics (BJS)
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Home  | Terms & Definitions: Corrections | Local jail inmates and jail facilities
Terms & Definitions: Local jail inmates and jail facilities

All persons booked into and housed in jail facilities by formal legal document and the authority of the courts or some other official agency, including repeat offenders booked on new charges and persons sentenced to weekend programs or entering the facility for the first time. They exclude inmates re-entering the facility after an escape, work release, medical appointment, stay in a treatment facility, and bail or court appearance.

Average daily population
The sum of inmates in jail each day for a year, divided by the number of days in the year.

Design capacity
The number of inmates that planners or architects intended for the facility.

Expected average length of stay
The average daily population (ADP) divided by the number of annual admissions, then multiplied by the number of days in a year.

Incarcerated population
Incarcerated population is the population of inmates confined in a prison or a jail. This may also include halfway houses, boot camps, weekend programs, and other facilities in which individuals are locked up overnight.

Indian country jails
Indian country adult and juvenile detention centers, jails, and other correctional facilities operated by tribal authorities or the Bureau of Indian Affairs, U.S. Department of the Interior.

A confinement facility generally operated under the authority of a sheriff, police chief, or county or city administrator. A small number of jails are privately operated. Regional jails include two or more jail jurisdictions with a formal agreement to operate a jail facility. Facilities include jails, detention centers, county or city correctional centers, special jail facilities (such as medical or treatment centers and pre-release centers), and temporary holding or lockup facilities that are part of the jail's combined function. Jails are intended for adults but can hold juveniles before or after their cases are adjudicated.

Jail incarceration rate
The number of inmates held in the custody of local jails, per 100,000 U.S. residents.

Jail inmates
Offenders confined in short-term facilities that are usually administered by a local law enforcement agency and that are intended for adults but sometimes hold juveniles before or after adjudication. Jail inmates usually have a sentence of less than 1 year or are being held pending a trial, awaiting sentencing, or awaiting transfer to other facilities after a conviction.

Jail jurisdiction
A county (parish in Louisiana) or municipal government that administers one or more local jails and represents the entity responsible for managing jail facilities under its authority. Most jail jurisdictions consist of a single facility, but some have multiple facilities or multiple facility-operators.

A unit of government or the legal authority to exercise governmental power. In corrections, it refers to the government that has legal authority over an inmate (state or federal). Prisoners under a given state's jurisdiction may be housed in another state or local correctional facility.

Midyear population
The number of inmates held in custody on the last weekday in June.

Operational capacity
The number of inmates that can be accommodated based on a facility's staff, existing programs, and services.

Percent of capacity occupied at midyear
The jail population at midyear, divided by the rated capacity.

Persons under jail supervision but not confined
All persons in community-based programs operated by jail facilities, including electronic monitoring, house arrest, community service, day reporting, and work programs. This group excludes persons on pre-trial release who are not in community‐based programs run by jails; persons under supervision of probation, parole, or other agencies; inmates on weekend programs; and inmates who participate in work‐release programs and return to jail at night.

Compared to jail facilities, prisons are longer-term facilities owned by a state or by the federal government. Prisons typically hold felons and persons with sentences of more than a year; however, the sentence length may vary by state. Six states (Connecticut, Rhode Island, Vermont, Delaware, Alaska, and Hawaii) have an integrated correctional system that combines jails and prisons. There are a small number of private prisons, which are facilities run by private prison corporations whose services and beds are contracted out by state or federal governments.

Rated capacity
The number of beds or inmates assigned by a rating official to institutions within the jurisdiction.

Persons released after a period of confinement (e.g., sentence completions, bail or bond releases, other pre-trial releases, transfers to other jurisdictions, and deaths). Releases include persons who have completed their weekend program and who are leaving the facility for the last time. They exclude temporary discharges, such as work releases, medical appointments, stays in treatment centers, court appearances, furloughs, day reporting, and transfers to other facilities within the jail jurisdiction.

Total correctional population
Total correctional population is the population of persons incarcerated, either in a prison or a jail, and persons supervised in the community, either on probation or parole.

Total incarceration rate
The number of inmates held in the custody of state or federal prisons or in local jails, per 100,000 U.S. residents.

Total inmates in custody count
To have custody of a prisoner, a state or the Federal Bureau of Prisons (BOP) must physically hold that person in one of its facilities. A state may have custody of a prisoner over whom another state maintains jurisdiction. This count includes inmates held in any public facility run by a state or the BOP, including halfway houses, camps, farms, training/treatment centers, and hospitals. This number includes the number of inmates held in local jails as reported by correctional authorities in the Annual Survey of Jails.

Weekly inmate turnover rate
The sum of weekly admissions and releases, divided by the average daily population (ADP). This rate is an indicator of the fluctuation of the jail population.

Year-end population
The number of inmates held in custody on December 31. The year-end population is typically smaller than the midyear population.

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