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A range of law enforcement activities are utilised by law enforcement agencies to disrupt illegal drug markets. However, little is known about their impact on violence levels. Understanding which law enforcement efforts reduce or increase serious violence is critical to reducing the harms created from illegal drug markets without producing further negative effects.
The UK Home Office commissioned RAND Europe to conduct a systematic review on the global literature in English, Dutch, Spanish and Portuguese on the impact of drug-related law enforcement activity on serious violence and homicide between 2011 and 2024, specifically answering the research question: What is the impact of drug-related law enforcement activity on serious violence and homicide?
33 studies were included in the review, with 23 studies were conducted in North America, 8 in South America, 2 in Europe and 1 in Asia. Drug-related law enforcement activities were categorised into eight categories: selective enforcement of a specific area or group, leadership removal, attack or removal of a drug trafficking organisation member, arrest or charges for drug law violations, crop eradication, drug seizures, militarised interventions, and multijurisdictional anti-drug coordination and resourcing.
This research aimed to help inform the work the Home Office and other government departments are undertaking to implement the Government’s Drugs Strategy ‘From Harm to Hope: a 10-year drugs plan to cut crime and save lives’.
Overall, the available evidence suggests that drug-related law enforcement activities are of limited effectiveness in reducing violence. More studies demonstrated an association between drug-related law enforcement activities and increased violence than decreased violence. Selective enforcement tactics appeared the most promising in their capacity to reduce violence, although the evidence base covered in this review is limited.
Passive drug-related law enforcement activities, such as increasing police presence in known drug-market areas, appear promising in reducing violence. However, less evidence is available on the effectiveness of these interventions than on active law enforcement activities.
The causal mechanisms of violence reduction are underexplored in the literature. However, several studies discussed supply disruptions, focused deterrence and positive relationships between police and communities as potential success factors.
Barriers to the effectiveness of violence reduction efforts included the resilience of drug markets, the cultural significance of violence in some drug-trafficking organisations, and law enforcement’s limited resources.
This review did not identify any UK-based evidence – most research came from the Americas. While most law enforcement activities in this review also occur in the UK, the results are not directly replicable in a UK setting.
Evidence on the relationship between drug-related law enforcement and serious violence and homicide over the last decade is lacking. What was previously effective (or ineffective) in reducing violence may yield different results now.
More evidence is needed on the effectiveness of drug-related law enforcement activities in retail-level markets or prison settings in reducing violence, two priority areas in the 10-year Drug Strategy.
Relevant agencies planning and implementing drug-related law enforcement activities as part of the Strategy should consider the risk of increased violence, particularly for interventions for which available evidence suggests a strong association (e.g. leadership removal and seizures).
Future UK research on drug-related law enforcement and violence could focus on interventions that may reduce violence, such as selective enforcement, and whether the findings presented can be validated.
Mafalda Pardal
Laura Atuesta
Fin Oades
Eric Sevigny
Emily Lawson
