The Prison Rape Elimination Act of 2003 (P.L. 108-79)
requires the Bureau of Justice Statistics (BJS) to carry out
a comprehensive statistical review and analysis of the incidence
and effects of prison rape for each calendar year.
Data were collected directly from inmates in a private setting using audio
computer-assisted self interview (ACASI) technology with a touch-screen laptop
and an audio feed to maximize inmate confidentiality and minimize literacy issues. A small number of inmates completed a short paper form. These were inmates housed primarily in administrative or disciplinary segregation or considered too violent to be interviewed.
A sample of 303 local jails was drawn to produce a 10 percent
sample of the 3,002 local jail facilities identified in the 2005
Census of Jail Inmates. The 2005 census was a complete
enumeration of all jail jurisdictions, including all publicly
operated and privately operated facilities under contract to
local jail authorities. The 2007 NIS was restricted to jails
that had more than five inmates on June 30, 2005. Based
on estimates from the 2007 Annual Survey of Jails, these
jails held an estimated 772,800 inmates aged 18 years or older on
June 29, 2007.
Of the 303 selected jails, 21 facilities were excluded from
the survey. Five facilities refused to participate in
the survey. Eight facilities were determined to be ineligible,
because more than 90 percent of inmates in each were prearraigned
or held for Immigration and Customs Enforcement
(ICE) or the United States Marshals Service or because the facility was a
community-based facility. Eight facilities were unable to participate
due to lack of space or staffing or because the jail was being renovated.
The number of inmates sampled in each facility varied
based on 5 criteria:
* an expected prevalence rate of sexual victimization of
* a desired level of precision based on a standard error of 1.75 percent
* a projected 70 percent response rate among selected inmates
* a 10 percent chance among participating inmates of not
receiving the sexual victimization questionnaire
* a prearraignment adjustment factor equal to 1 in facilities
where the status was known for all inmates, and less
than 1 in facilities where only the overall proportion of
prearraigned was known.
A total of 74,713 inmates were selected. After selection, an
additional 7,314 ineligible inmates were excluded -- 6,549 were
transferred to another facility before interviewing began, 676
were mentally or physically unable to be interviewed, and 89 were under the age of 18.
Overall, 45,414 inmates participated in the survey, yielding
a response rate of 67 percent. Approximately 90 percent of the participating
inmates (40,419) received the sexual assault survey.
A sample of 130 State prisons was drawn to produce a
10 percent sample of the 1,267 adult State confinement facilities
identified in the 2005 Census of State and Federal Adult
Correctional Facilities. The 2005 census was a complete
enumeration of state prisons, including all publicly operated
and privately operated facilities under contract to state
correctional authorities. The 2007 NIS was restricted to
confinement facilities - institutions in which fewer than
50 percent of the inmates were regularly permitted to leave,
unaccompanied by staff, for work, study, or treatment. Such
facilities included prisons, penitentiaries, prison hospitals,
prison farms, boot camps, and centers for reception, classification,
or alcohol and drug treatment. The 2007 NIS
excluded community-based facilities, such as halfway
houses, group homes, and work release centers. Also selected were 17 Bureau of Prisons-operated facilities and 3
private facilities. Of the 150 selected state and federal facilities, 4 were
excluded from the survey.
Inmates were selected using the same criteria as in Part 1. A total of 37,362
inmates were selected and 26,157 inmates participated in the survey, yielding
a response rate of 72 percent (after an additional 1,017 ineligible
inmates were excluded). Approximately 90 percent of the participating
inmates (23,398) received the sexual assault survey.
Part 1 -- Inmates in local jails in the United States.
Part 2 -- Inmates in adult confinement facilities, including prisons, penitentiaries, prison hospitals, prison farms, boot camps, and centers for reception, classification, or alcohol and drug treatment.
National Inmate Survey (NIS)