BJS conducts the COJ and the ASJ series to collect facility and jurisdiction level data on jail population.
Since 1970, the COJ has been administered periodically to about 3,200 county and city jails (local jails) nationwide and from the Federal Bureau of Prisons facilities that function as jails.
in 1982, the ASJ has been administered to a nationally representative sample of nearly 900 jail jurisdictions in years between censuses.
The COJ and the ASJ produce key statistics including jail population size and characteristics (e.g., sex, race, and conviction status); juvenile counts; admissions and releases; holds for other authorities; jail capacity and turnover rates.
The COJ collects facility-level data from all local jails nationwide and allows BJS to produce state-level key statistics.
In addition, it provides the sampling frame for BJSÃÂ¢ÃÂÃÂ jail surveys such as the ASJ and the Survey of Inmates in Local Jails.
The ASJ uses a nationally representative sample of jail jurisdictions selected from the most recent COJ frame on jails to annually produce national statistics on the jail population.