Objective: The objective of this study was to determine the effectiveness of the Crime Prevention Through Environmental Design (CPTED) approach in reducing robberies.
Methods: CPTED evaluations were obtained through a comprehensive search mechanism. Two sets of inclusion criteria were used: 16 primary studies evaluated a CPTED program with a comparison period; 12 secondary studies presented some evidence of CPTED effects but were not required to have the same level of scientific rigor. The percentage change in pre- and post-intervention events was the outcome examined. Studies were stratified by programs implementing multiple components, a single component, and through ordinances.
Main results: All primary multiple-component CPTED programs experienced a percentage change in robberies ranging from -84% to -30%. Single-component program effects ranged from -83% to +91%, and ordinances ranged from -65% to +130%. Secondary studies reported robbery changes ranging between -92% and +7.6%. Robbery reductions were larger for interventions comprising basic store design, cash control, and training components compared to those including equipment systems. No associations were found between robbery decreases and either the follow-up period or the number of program components. Studies examining nonfatal injuries found a median pre-post change of -61%; those examining homicides found changes ranging from 0% to +11%.
Conclusions: The broad nature of the CPTED approach allows its adaptation to any setting, and results indicate that it is an effective approach to reducing robbery. However, most interventions were not evaluated independently of other factors contributing to robbery risk. More research is needed on individual components and effects in various business settings.