Organised crime poses one of the greatest threats to national security and development in the 21st century. Despite this, most policy, data collection, and scholarly research focuses on individuals and disorganised violence. Our work addresses several critical gaps in knowledge: 1. What are the incentives for gangs to engage in violence and socially costly behaviour? 2. Which are the trade-offs that practitioners face when deciding how to engage with organised violence? 3. What type of information do relevant decision-makers need to inform their policies? 4. Which are the most relevant tools for tracking down gang behaviour and use of violence?