As funding permits.
The National Inmate Survey (NIS) is part of BJS's National Prison Rape Statistics Program, which gathers mandated data on the incidence and prevalence of sexual assault in correctional facilities under the Prison Rape Elimination Act of 2003 (PREA; P.L. 108-79). PREA requires a 10% sample of correctional facilities to be listed by incidence of sexual assault, with a minimum of one prison and one jail facility in each state. Data are collected directly from inmates in a private setting using audio computer-assisted self-interview (ACASI) technology with a touchscreen laptop and an audio feed to maximize inmate confidentiality and minimize literacy issues. See the methodology section in reports for sampling and weighting information.
The Prison Rape Elimination Act of 2003 (PREA; P.L. 108-79) requires a 10% sample of correctional facilities to be listed by incidence of sexual assault, with a minimum of one prison and one jail facility in each state. See the methodology section in reports for sampling and weighting information, which varies by collection year. Inmates are randomly assigned to receive either a survey of sexual victimization or a survey of mental and physical health, past drug and alcohol use, and treatment for substance abuse (questions from which are also used to pad out time for respondents completing the victimization survey quickly).