Popping the balloon effect: assessing drug law enforcement in terms of displacement, diffusion, and the containment hypothesis.

The "balloon effect" is an often used but rather dismissive representation of the effects of drug law enforcement. It implies a hydraulic displacement model and an impervious illicit drug trade. This paper reviews theoretical and empirical developments in policing and crime prevention. Based on this, 10 types of displacement are identified and four arguments developed: (1) Displacement is less extensive and harmful than often contended; (2) Where displacement may occur it preferably should be exploited as a policy tool to delay the illicit drug industry and deflect it to less harmful locations and forms; (3) The opposite of displacement occurs, termed a diffusion of drug control benefits, wherein law enforcement has benefits that extend further than envisaged, and has 10 types mirroring those of displacement; (4) The net impact of drug law enforcement is often underestimated, and a containment hypothesis may offer a more accurate framework for evaluation.