Do Cameras Reduce Crime? The Research
The primary justification for surveillance cameras is crime reduction. But what does the evidence actually show? The answer is more nuanced than either advocates or critics suggest.
What the research shows
Campbell Collaboration systematic review (2009, updated 2019): The most comprehensive meta-analysis of CCTV effectiveness. Key findings:
- CCTV is associated with a modest (13-16%) reduction in crime overall
- Effects are strongest in parking lots and garages
- Effects are weakest in city centers and public housing
- Drug crime and violent crime show the least impact
- Property crime shows the most impact
UK Home Office studies: Found CCTV most effective when combined with other interventions (lighting, design changes, community policing). Cameras alone had minimal impact.
Chicago studies: Found that cameras on the most crime-prone Chicago blocks were associated with modest crime reductions, but with significant displacement (crime moving to adjacent areas).
The displacement problem
When cameras reduce crime in one area, it often moves:
- Geographic displacement: Crime shifts to areas without cameras
- Temporal displacement: Crime shifts to times when cameras are less monitored
- Method displacement: Criminals adapt their techniques
- Target displacement: Criminals choose different victims
If cameras displace rather than prevent crime, the aggregate effect on public safety may be minimal while the surveillance infrastructure remains permanent.
What cameras definitely do
Regardless of crime reduction:
- Evidence collection: Cameras provide footage for investigation after crimes occur
- Witness corroboration: Camera footage supports or contradicts witness testimony
- Behavioral modification: People in camera-visible areas modify behavior (both criminal and non-criminal)
- Situational awareness: Monitoring personnel can coordinate emergency response
The cost-benefit question
Installing and maintaining a camera costs $2,000-$10,000 per unit plus ongoing storage and monitoring. Studies suggest that equivalent investment in street lighting, community programs, or environmental design may produce larger crime reductions.
This doesn’t mean cameras are useless. It means the decision to install them should be evidence-based, not assumed.
Why this matters for Sentinel
Sentinel maps cameras without judgment about whether they’re justified. Understanding that the evidence for crime reduction is mixed helps you evaluate surveillance proposals in your community.