To fulfill part of its mission, the Bureau of Justice Statistics (BJS) conducted the Survey of Prison Inmates (SPI), a national, wide-ranging survey of prisoners age 18 or older who were incarcerated in state or federal correctional facilities within the United States. SPI provides national statistics on prisoner characteristics across a variety of domains, such as current offense and sentence, incident characteristics, firearm possession and sources, criminal history, demographic and socioeconomic characteristics, family background, drug and alcohol use and treatment, mental and physical health and treatment, and facility programs and rules violations. SPI can also be used to track changes in these characteristics over time, describe special populations of prisoners, and identify policy-relevant changes in the state and federal prison populations. Formerly the Survey of Inmates in State and Federal Correctional Facilities (SISFCF), this survey was renamed SPI with the 2016 iteration.