Abstract
In this article, we test whether an isolated information campaign can deter criminals by appealing to their apprehension risk perception. A randomized trial was conducted around 154 high crime housing blocks in Bogotá. With support of the Colombian Police, half of the blocks were exposed to a three month poster campaign reporting the number of "arrests around this street block" and half to a no-treatment control condition. The main outcome measure (total registered crime) and secondary outcome measures (calls to the emergency line for thefts and attacks, and minor wrongdoings) were provided by the Police. Additionally, trust in police, security perception, and police performance perception were measured among residents and workers in the treatment and control areas (N = 616) using a post-treatment survey. Measures were analyzed with linear regression analysis and two-sample t-tests. Over the course of the treatment period, premeditated crime was reduced, while spontaneous crime remained unchanged. Overall levels of crime were not significantly altered. Also, a moderate crime reduction is detectable during the first month of the treatment period. The posters were highly visible (93% of respondents in the treated areas recalled them) and positively received (67% "liked" them). Perceptions of security and police among locals improved, though not significantly. Inherent among residents of Bogotá is a pervasive feeling of impunity and low trust in authorities, making the city a hard test case for an offender-targeted advertising campaign. Initial reductions of crime and overall reductions of premeditated crime are thus noteworthy. These results align with key principles of apprehension risk updating theory.