Electronic monitoring of offenders
Evidence-rated crime-reduction intervention (EMMIE).
Effect on crime
mixed evidence
Evidence quality
very strong
Cost
moderate
What the evidence says
Electronic monitoring (EM) involves placing a tag on an offender's ankle or wrist to verify their whereabouts. The evidence suggests mixed findings regarding its impact on crime; some studies indicate reduced reoffending, particularly among sex offenders, while others show increases or no significant effect. This summary is based on systematic reviews of multiple studies from various countries, highlighting that successful implementation hinges on technology, communication, and clear guidelines.
How it works
EM increases the likelihood of being caught for offenses due to enhanced monitoring. It allows offenders to maintain family contact and employment, potentially deterring criminal behavior by altering their environment and responsibilities.
Implementation
Successful implementation requires good communication between multiple agencies, clear program design, and adequate technological support. Administrative strategies and prompt responses to breaches are crucial for managing compliance.
Source: College of Policing Crime Reduction Toolkit (What Works Centre for Crime Reduction). Summarised 2026-07-15. BlueLineHub is independent and not affiliated with the College of Policing.