The purpose of this evaluation was to determine the effectiveness of the global positioning system (GPS) monitoring of high-risk gang offenders (HRGOs) who are placed on parole.
Data on high risk gang offenders (HRGOs) (Subject Data, n = 784 and Outcomes Data, n = 18,816) were collected from the California Department of Corrections and Rehabilitation (CDCR), official arrest records, and parole supervision records.
California operates a data management system that houses numerous databases relevant to the supervision of HRGO parolees. The majority of the data used for this study were derived from three databases: Cal-Parole, the Revocation Scheduling and Tracking System (RSTS), and the Offender-Based Information System (OBIS). Offenders are linked across all of these systems through a unique identifier that permits users to identify the same individual in different contexts or data systems.
Another principal data source for this study was the official record of arrests, convictions, and custody (commonly known as a RAP sheet) of each study participant. These data were provided in a hardcopy format and coded by hand into a database developed specifically for the study.
A third data source included the record of supervision for each parolee. Specifically, the parole agent notes the date and specific type of contact. These data were collected to measure the level of supervision received by each offender.
GPS monitoring data (GPS Assignment Data, n = 1014 and GPS Event Data, n = 281) was collected from two vendors: Satellite Tracking of People (STOP) LLC and Pro Tech. Each vendor provided the following data: a profile of the offender, a record of each event (inclusion/exclusion zone, strap tamper, low battery, cell communication gap, and no GPS communication) that included the event start and stop times and duration during a specific period, and the assignment history of the device.
The CDCR Parole Agent survey (Parole Agent Survey Data, n = 24) was emailed to Level 1 GPS Parole Agents with existing gang offender caseloads in August 2012. The email contained a note introducing the anonymous web-based survey, instructions for taking the survey, a link to the survey, and a password to securely access it. Parole Agents were sent numerous requests to complete the survey throughout the month; the survey was closed at the end of September 2012.
Costs information (Costs Data, n = 33) on personnel, facilities, equipment and materials, and other inputs were obtained through communications with CDCR staff and a review of budget documents. A cost-effectiveness worksheet was developed by research staff and transmitted to CDCR staff by electronic communication with a request to add the monetary values to each category along with explicit instructions to add any cost element that was missing from the initial draft. Follow-up discussions were used to refine cost elements and associated monetary values. For verification and to correct the cost elements, a final version of the worksheet was transmitted to a CDCR budget analyst.
The study focuses on high-risk gang offenders (HRSOs) who were released from prison and placed on parole supervision with GPS monitoring in six California jurisdictions. This group (n = 407) includes all HRGOs placed on GPS monitoring technology from March 2006 through October 2009 in each of the six specialized gang units located in the City of Los Angeles and the following California counties: Fresno, Los Angeles, Riverside, Sacramento, and San Bernardino.
To identify comparison individuals likely to have pretreatment risk characteristics similar to those in the treatment group, a propensity score procedure was performed using a sample of offenders drawn from each of the same six communities that maintained specialized gang units, but who were not place on GPS at the time of data collection.
The study used the one-to-one nearest-neighbor matching method. The treatment group was matched on race, age, gender, admit status, controlling offense type, controlling offense severity, registration as a violent offender, narcotics offender or sex offender, drug and alcohol testing requirements, date of parole, and parole district. A propensity score was generated for each parolee. The PSMATCH2 program for STATA matched control and treatment group parolees to unique nearest neighbors whose propensity score was with a certain caliper. Parolees who could not be matched were dropped. The matching procedure resulted in a final sample of 784 subjects (392 treatment and 392 control subjects). The two groups did not differ significantly on any variable.
The California Department of Corrections and Rehabilitation (CDCR) Parole Agent Survey (Parole Agent Survey Data, n = 24) was sent to all Level 1 GPS Parole Agents with existing gang offender caseloads in August 2012.
Longitudinal: Cohort / Event-based
All high risk gang offenders (HRGOs) placed on parole in the City of Los Angeles and the following California counties: Fresno, Los Angeles, Riverside, Sacramento, and San Bernardino, between March 2006 and October 2009 and all parole officers in the same jurisdictions who had HRGO offenders in their case loads.
Parole monitoring program
administrative records data
The Subject Data file (n = 784 and 133 variables) has demographic variables (age, race and sex) on the high risk gang offenders (HRGOs), offense type (drug, property, violent crime, other) and severity, number of charges, number of prior arrests by offense type, gang conditions, number of days on parole, number of days in custody, GPS monitoring condition, and study site.
The Outcomes Data file (n = 18,816 cases and 45 variables) includes variables on arrest and parole violations for each month of the study period. The offenders' parole start and end dates, as well as age at parole date are also included.
The GPS Assignment Data file (n = 1014 and 17 variables) includes offender's year of birth, parole date, GPS assignment start and stop dates, and number of days on GPS monitoring.
The GPS Event Data file (n = 281 and 18 variables) includes the offender's parole start date, study end date, the GPS vendor, the type of GPS violation and number of violations.
The Parole Agent Survey Data file (n = 24 and 94 variables) includes parole agent demographics (gender, year of birth, and highest level of education), number of years as a parole agent, how long the respondent has worked in the GPS monitoring unit, and if the respondent has gang offenders on their caseload. Other variables ask about the types of equipment the agent has been issued (cell phone, hand held GPS unit, laptop, wireless card, installation tools and straps) and how often the agent has problems with the equipment. Other variables include topics covered during offender orientation, how quickly the agent responds to various types of violations alerts. Additional variables ask the agent about the GPS monitoring system, training, reliability, enhancing traditional parole supervision, and effects on outcomes for parolees.
The Costs Data file (n = 33 and 5 variables) include cost information for GPS parole and standard parole including personnel, facilities, equipment and supplies, and other inputs.
The response rate for the Parole Agent Survey was 83.3 percent.