Survey of Sexual Victimization in Adult Correctional Facilities, United States, 2020

A census was completed for state adult prisons systems, the federal BOP, military correctional facilities, and facilities operated by U.S. Immigration and Customs enforcement (ICE). Samples were collected of the four main other types of adult correctional facilities. A sample of 700 public jails was drawn from the frame of BJS's 2019 Census of Jails. There were 5 total strata with the largest facilities in each state and any facilities with an average daily population of 1000 or more selected with certainty and the remaining three strata selected facilities using stratified random sampling. A sample of 15 private jails were also selected from the COJ frame; a stratum of certainty units included facilities with an ADP of 1000 or more and a stratum of noncertainty units was selected using probability proportional to size (PPS) methods. There were 155 private prison facilities selected from an updated frame of the 2019 Census of State and Federal Adult Correctional Facilities (CCF). Facilities with an ADP of 305 or more were selected with certainty and the remaining non-certainty units were selected using PPS. A sample of 25 tribal jails were selected from the 2019 frame of the Annual Survey of Jails in Indian Country. Tribal jails with an ADP of 73 or more were selected with certainty and the remaining 16 were selected using PPS.

Private Prisons: All facilities were first sorted by ADP and a pre-determined cut-off (ADP greater than or equal to 305) was used to determine certainties-due-to-size units. The facilities remaining in the frame at this point were sorted by region (i.e., Northeast, Midwest, South, or West), state, and ADP, and sampled systematically with probability proportional to size.

Public Jails: Public jails were stratified into two certainty strata and three noncertainty strata. For the first stratum, the largest jail jurisdictions in 45 states and the District of Columbia were selected to meet the PREA requirement that at least one jail per state is selected each year. For the second stratum, all other jail jurisdictions with ADPs greater than or equal to 1,000 inmates were selected with certainty. The remaining jail jurisdictions on the frame were grouped into three strata. The cum-root-f method was used to determine the boundaries of these three strata based on ADP as the measure of size (Cochran, 1997). The Large ADP stratum included jails with ADP 281 to 999. The Medium ADP stratum included jails with ADP 92 to 280. The Small ADP stratum included jails with ADP 91 or smaller. The jail jurisdictions in each of these three strata were then sorted by region, state, and ADP and selected systematically.

Private Jails: Jails with an ADP of 1,000 or more were selected with certainty-due-to-size. The remaining private facilities were sorted by region, state, and ADP, and were systematically sampled with probability proportional to size.

Indian Country Jails: Facilities were sampled with certainty due to a pre-determined ADP cut-off (ADP greater than or equal to 73). The remaining facilities on the frame were sorted by state and ADP then sampled with probability proportionate to size. Facilities in Indian country housing exclusively juveniles were excluded from the adult sample.