All 50 states, the District of Columbia, and the federal government use electronic devices to monitor the movements and activities of pretrial defendants or individuals on probation or parole.
The current technology of choice is Global Positioning Systems (GPS).
A detailed report by The PEW Charitable Trusts released in 2015 reported that, “a sharp increase in the use of GPS technology accounted for all of the 10-year growth in electronic tracking.”
These findings are consistent with published studies that suggest, Radio Frequency (RF) devices are giving way to more advanced technology that can track participants in real-time.
In addition, the National Criminal Justice Technology Research, Test, and Evaluation Center at Johns Hopkins reported, that while the number of GPS monitors in use has grown rapidly, the percentage of monitored individuals on both GPS and RF has remained relatively consistent since 1990, estimated at around 4% of the population on community supervision as of 2013.
Accuracy of GPS Technology
GPS satellites broadcast signals in space with a certain accuracy, but reception depends on additional factors including satellite geometry, signal blockage, atmospheric conditions, and receiver design features/quality.
GPS-enabled smartphones are typically accurate within a 4.9 m (16 ft.) radius in ideal conditions.
Real-time positioning can be achieved within a few centimeters, and long-term measurements at the millimeter level with dual-frequency receivers and/or augmentation systems.
With GPS III, the next generation of GPS satellites being designed and built by Lockheed Martin, signals will be three times more accurate than the current generation.
According to the National Institute of Justice, recidivism refers to an individual’s relapse into criminal behavior, often after the individual receives sanctions or undergoes intervention for a previous crime. Recidivism is measured by acts that result in rearrest, reconviction, or return to prison either with or without a new sentence during a three-year period following release.
Four Studies that Support GPS in Reducing Recidivism Rates
First, a 2018 study by the University of Ontario Institute of Technology found:
- Individuals on electronic monitoring supervision were far less likely to have a Failure to Appear violation (8.17% vs. 22.59%) than those who were not electronically monitored.
The second study from the U.S. Department of Justice Office of Justice Programs and National Institute of Justice showed that electronic monitoring:
- Reduces an individual’s risk of failure by 31%.
- Specifically, GPS typically has more of an effect on reducing failure to comply than RF systems.
- Had less of an impact on individuals involved in a violent crime than on sex, property, drug-involved individuals. However, the effect remains statistically significant.
The third from the U.S. Federal Court System reports:
- 99% of pretrial defendants on federal location monitoring remain free of any arrest for a violent offense during supervision.
- 86% of individuals placed on location monitoring at the time of sentencing remained free of any new arrest, during their term of supervision.
- 97% of individuals placed on location monitoring at the time of sentencing remain free of any arrest for a violent offense, during their term of supervision.
Finally, the American Correctional Association study concluded:
- GPS monitoring was more effective than traditional parole in reducing recidivism and was also more cost-effective. Parolees in the traditional group — those not placed on GPS monitoring — committed new crimes and had their parole revoked more often than individuals in the GPS group. The traditional group’s recidivism rate was 38% higher than that of the GPS group.
According to these studies, GPS monitoring provides an effective and efficient solution to reduce recidivism, which in turn could help alleviate the burden of overcrowding and reduce facility costs.