Data Source

Data for the current study was extracted from the FDOC’s Offender Based Information System (OBIS). OBIS contains detailed offender characteristics, sentencing, and correctional experience data on all felony offenders sentenced to state prison or a state supervision term. Each offender is assigned an offender identification number that is used for all commitments to the FDOC. Data exists for all offenders who have been sentenced to prison or supervision since 1980. Therefore, detailed prior and subsequent conviction and sentencing information is available for cohorts of prison releases since that time.

Additionally, the OBIS system contains detailed information on every movement, and the associated dates and times of movements, of offenders in and out of the correctional system, and between correctional facilities. This data is used by the system to manage and account for inmates at all times and is therefore complete and accurate. Comprehensive information relating to every sentencing event including the offense and sentencing dates, type of sentences, and the convicted offense(s) are also contained in OBIS. In addition, data on demographic variables, disciplinary infractions, classification decisions, and scores on the Tests of Adult Basic Education (TABE) are captured in the database.

To measure recidivism and account for effects of factors known to influence recidivism rates, this study relied on a comprehensive data file developed previously by the FDOC’s Bureau of Research and Data Analysis (FDOC, 2003). That data includes 88,678 releases for 81,737 inmates released from July 1995 through June 2001, for which no data was missing on important inmate characteristics relevant to recidivism.⁷ The 74,467 males inmates account for 80,919 releases, and 7,270 females inmates account for 7,759 releases. Only first releases are counted for each prison commitment. Releases subsequent to a return to prison for technical violation of supervision conditions are not treated as additional releases, since this would artificially lower the recidivism rate.

For this research, new data were extracted from FDOC’s data files to create multiple treatment and control groups from among inmates based on their levels of exposure to private prisons in order to analyze differences in recidivism rates. These experimental group definitions relied primarily on detailed data on inmate movements from FDOC reception centers through public and private prisons and other department facilities. Within and for each prison commitment, these data allow determination of the type of facility inmates were released from, the length and percentage of prison time spent in private prisons, and the proximity of exposure to private prisons and an inmate’s release.

7. Virtually all excluded cases were missing scores on the Tests of Adult Basic Education because they did not take the test. The Department’s analysis indicates these missing cases had recidivism rates somewhat lower than the retained cases.