The effect of business improvement districts on the incidence of violent crimes

Objective To examine whether business improvement districts (BID) contributed to greater than expected declines in the incidence of violent crimes in affected neighbourhoods. Method A Bayesian hierarchical model was used to assess the changes in the incidence of violent crimes between 1994 and 2005 and the implementation of 30 BID in Los Angeles neighbourhoods. Results The implementation of BID was associated with a 12% reduction in the incidence of robbery (95% posterior probability interval -2 to 24) and an 8% reduction in the total incidence of violent crimes (95% posterior probability interval -5 to 21). The strength of the effect of BID on robbery crimes varied by location. Conclusion These findings indicate that the implementation of BID can reduce the incidence of violent crimes likely to result in injury to individuals. The findings also indicate that the establishment of a BID by itself is not a panacea, and highlight the importance of targeting BID efforts to crime prevention interventions that reduce violence exposure associated with criminal behaviours.