BJS uses criminal history records to study the number and types of crimes committed by state prisoners both prior to and following their release. The first study tracked a sample of state prisoners released in 11 states in 1983, and the second study followed a sample of state prisoners released in 15 states in 1994. Both studies had a 3-year follow-up period. The latest study tracked a sample of prisoners released in 34 states in 2012 for 5 years after release. These studies documented the arrest, conviction, and incarceration experiences of the former inmates within and outside of the state that released them.
States were selected for the 2012 prisoner recidivism study based on their ability to provide prisoner records and the FBI or state identification numbers on persons released from state correctional facilities in 2012. This study estimated the recidivism patterns of more than 400,000 persons released in 2012 from state prisons in 34 states. In 2012, these 34 states were responsible for 79% of all persons released from state prisons nationwide. A representative sample of inmates released in 2012 was developed for each of the 34 states using data reported by state departments of corrections to BJS's National Corrections Reporting Program (NCRP), yielding a final sample of approximately 92,000 persons. BJS used the state and FBI identification numbers supplied by the departments of corrections to collect national criminal history records on the sample of former prisoners.
Given the changes in the characteristics of the U.S. prison population, an increase in the number of states participating in the study, and differences in the lengths of the follow-up periods, direct comparisons of the recidivism estimates from the study on prisoners released in 34 states in 2012 should not be made to those from the previous BJS prisoner recidivism studies. For more information on the factors that affect the comparability of the estimates from the BJS prisoner recidivism studies, see Recidivism of Prisoners Released in 30 States in 2005: Patterns from 2005 to 2010 (NCJ 244205, BJS web, April 2014).