25 July 2017

Research published on electronic monitoring

Dr Jyoti Belur and Dr Amy Thornton of UCL Department of Security and Crime Science talk about the newly-published systematic review on electronic monitoring.

What is electronic monitoring?

Electronic monitoring (EM) involves placing a tag around the ankle or wrist of an individual or suspect which, in combination with a receiving device, can verify their whereabouts to establish remotely whether the individual is violating a set of pre-established conditions determined by the courts. These might be restrictions in terms of the areas where the individual should not be or in terms of a curfew meaning they have to remain in a fixed location (their house for example) during certain hours in a day. 

The ability to monitor an offender's whereabouts means that the offender can be released into the community rather than serving time in a prison. EM devices use either radio frequency or GPS technology to send information in real time or with a delay. It can be applied at any stage in the criminal justice process- either before trial, or as early release from prison, or even as an alternative to prison. Adults as well as juveniles, can be monitored.

What did the systematic review tell us about the impact of electronic monitoring on reducing crime?

Overall when taken together, studies showed that there was a reduction in (re)offending by those on EM as compared to those who were not, but this was not statistically significant. EM seems to be effective for sex offenders as it showed a statistically significant reduction in reoffending for this group. It also had a statistically significant effect on reducing reoffending in offenders who were put on EM instead of being sent to prison, as compared to those who were sent to prison. We think this might be because prison can expose individuals to other criminals and bad influences, whereas monitoring allows them to remain within the confines of their home environment.

How does electronic monitoring reduce crime?

EM increases the risk of being caught (re)offending because it allows the authorities to be alerted if the individual is either not at a specified location when they are expected to be (such as at home overnight), or if they have entered an exclusion zone (such as a playground). Offenders on location tracking devices or GPS may also be linked to, or indeed cleared, of crimes if their device shows that they were either present at or absent from, a crime scene when the crime was committed.  Monitoring may also increase the effort required to offend as they need to remove or damage the tag, which is difficult to do. 

How do you implement electronic monitoring to ensure the best impact?

Our review identified a number of implementation challenges. These included technological issues such as equipment malfunction, loss of signal or power and battery failure. EM programmes require good communication and co-ordination between a number of agencies like the courts, prisons, probation service, the police, and private monitoring companies. Most importantly, unless the response to a breach is prompt and swift, participants have little incentive to respect their curfew times and other conditions.   

What about cost-effectiveness?

While there was not enough information to conduct a cost-benefit analysis, our review identified a lot of information regarding the costs of various monitoring programmes and the potential savings that they may make when compared to imprisonment.

We can say that the use of radio frequency technology for monitoring is less expensive as compared to using GPS technology. Active monitoring, in real time for 24 hours a day, is more expensive than passive monitoring when the data is uploaded once a day to monitor participants. Overall we can say it is less expensive when compared to prison but more expensive than traditional supervision or probation.

You can download the full systematic review, research protocol  and other resources by visiting the Electronic monitoring page of our What Works: Crime Reduction Systematic Review Series.