Effect of urban closed circuit television on assault injury and violence detection

Abstract

Objective: To evaluate the effect of closed circuit television (CCTV) surveillance on levels of assault injury and violence detection. Design: Intervention versus control study design. Setting: Five town/cities with CCTV surveillance and five, matched control centres without CCTV surveillance in England. Intervention: CCTV installation and surveillance. Methods: Assault related emergency department attendances and violent offences recorded by the police in CCTV and control centres in the four years, 1995-99, two years before and two years after CCTV installation, were compared. Results: Assault related emergency department attendances decreased in intervention centres (3% decrease, ratio 0.96; 95% confidence interval (CI) 0.93 to 0.99) and increased in control centres (11% increase, ratio 1.11; 95% CI 1.08 to 1.14). Overall, changes in emergency department assault attendance in CCTV and control centres were significantly different (t test, p<0.05). Police recorded violence increased in CCTV (11% increase, ratio 1.16; 95% CI 1.08 to 1.24) and control centres (5% increase, ratio 1.06; 95% CI 0.99 to 1.13). Overall, changes in police recording in CCTV and control centres were not significantly different (t test, p>0.05). In CCTV centres, decreases in assault related emergency department attendances and increases in police violence detection were not uniform. Conclusion: CCTV surveillance was associated with increased police detection of violence and reductions in injury or severity of injury. CCTV centre variation deserves further study.