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Survey of Inmates in Local Jails (SILJ)
Data Collection Status
Active
Frequency
1972, 1978, 1983, 1989, 1996, and 2002
Latest Data Available
2002
Data Experts
Todd Minton, BJS Statistician
Collection Period
1996, 2002
Description
Conducted periodically, the Survey of Inmates in Local Jails (SILJ) provides information on individual characteristics of jail inmates, current offenses and detention status, characteristics of victims, criminal histories, family background, gun possession and use, prior drug and alcohol use and treatment, medical and mental health history and treatment, vocational programs and other services provided while in jail, as well as other personal characteristics. Data are collected through personal interviews with a nationally representative sample of inmates in local jails. The survey utilized a two-stage sample design in which jails were selected in the first stage and inmates within local jails were selected in the second stage. Comprehensive national data on jail inmates are vital to understanding changing correctional populations, the financial and societal costs of incarceration, and alternative sanctions. The SILJ is the only national source for these data and was last administered in 2002.
The sample for the 2002 survey was selected from the universe of all jails in the United States, which were enumerated in the 1999 Census of Jails. The sample design was a stratified two-stage selection in which jails were selected in the first stage and inmates to be interviewed were selected in the second stage. In the first sampling stage, six separate strata were formed based on the size of the male, female, and juvenile populations in each jail. In strata one and two, all jails were selected to ensure jails with large numbers of males, females, or juveniles had a higher probability of selection than jails with a small inmate population. The weighting procedure consisted of a base weight for each inmate and four adjustment factors that produced the final weight for the survey. Data were collected through face-to-face interviews with jail inmates using computer-assisted personal interviewing.
Periodically, changes are made to the questionnaires to improve measurement and to collect new information on evolving issues in criminal justice and topics of greatest interest to the field and data users. Recent modifications include enhanced questions on medical and mental health histories of inmates. In 2002, the sample design was modified to ensure a representative sample of juveniles being held in local jails.
SILJ 2024-2025
After several years of research and development, BJS conducted the latest iteration of the Survey of Inmates in Local Jails (SILJ) between November 2024 and April 2025. Comprehensive national data on jail inmates are vital to understanding changing correctional populations, the financial and societal costs of incarceration, and alternative sanctions. The SILJ is the only national source for these data and was last administered in 2002.
Since 2002, new issues and policy concerns emerged that merited coverage in the new SILJ. BJS enhanced the measurement of physical and mental health characteristics and drug and alcohol use, abuse, dependence, and treatment. Inmates’ experiences with physical and mental health care in jail, fines and fees paid by inmates for jail services, and re-entry programs offered by jails are important policy topics that were reflected in the new SILJ. See the 2024-2025 SILJ webpage for more information.
