A systematic review by the Campbell Collaboration evaluated the impact of seven police action strategies focused on the seizure of illegal firearms. The actions were carried out in the cities of Kansas, Indianapolis, Pittsburgh (USA), as well as Cali and Bogotá (Colombia). A reduction in homicide rates was observed in six of the seven tests evaluated. In Pittsburgh, there was a 34% reduction in calls regarding shootings and a 71% reduction in calls involving firearm injuries. In Kansas City, there was a 29% reduction in homicides, whereas in Bogotá and Medellín, there was a 10% to 15% reduction in homicides [1].
However, the authors of the systematic review report that those conclusions need to be relativized and that caution should be exercised when generalizing those findings due to the small number of studies, the variability in the design of the studies, and the analytical strategies adopted, the previous differences between the areas of intervention and comparison, and the scarcity of data on factors such as the quality of implementation, the spatial displacement of offences, and the long-term impact.