In August of 2007, the California Department of Corrections and Rehabilitation (CDCR), Division of Adult Parole Operations (DAPO) initiated a 60 day field test of two-piece Global Positioning System (GPS) units for parolee monitoring. The field test was designed to answer the question: How does a two-piece GPS system perform relative to a one-piece GPS system? The Center for Evidence-Based Corrections was asked by DAPO to report on the results of the field test.
The Center analyzed data provided by the GPS vendors and DAPO on GPS alert activity, unit replacement, and workload impact. The Center also gathered qualitative information on two-piece GPS performance through interviews with parole agents and DAPO staff involved with the field test, as well as focus groups of parolees. The degree to which results of the field test can be generalized is limited by the small number of GPS units included in the field test and the fact that the performance of two-piece GPS units deployed solely for the field test period was compared to the performance of one-piece units that DAPO had been using in the field for two years prior to the field test.
