A 2009 analysis by Northeastern University and the University of Cambridge, "Public Area CCTV and Crime Prevention: An Updated Systematic Review and Meta-Analysis," examined 44 different studies that collectively surveyed areas from the United Kingdom to U.S. cities such as Cincinnati and New York.The analysis found that:
- Surveillance systems were most effective in parking lots, where their use resulted in a 51% decrease in crime;
- Public transportation areas saw a 23% decrease in crimes;
- Systems in public settings were the least effective, with just a 7% decrease in crimes overall. When sorted by country, however, systems in the United Kingdom accounted for the majority of the decrease; the drop in other areas was insignificant.