The Matrix in Context: Taking Stock of Police Gang Databases in London and Beyond

Technology has ushered in a new era of intelligence-led and “big data” policing, and police gang databases are part of this paradigmatic shift. In recent years, however, gang databases have come under intense public scrutiny. For example, Amnesty International and others argue that London’s Gangs Matrix is discriminatory and violates data-protection laws. This paper draws on evidence and examples from a wide range of sources—gang legislation, surveys of young people, police gang records, and research on gangs—to put the Matrix controversy into broader context, and to adjudicate between common validity and civil liberties critiques of gang databases. We find there is merit to civil liberties concerns and, to a lesser extent, claims that gang data are invalid and unreliable, but the picture is more complex than law enforcement or advocacy groups make it out to be. We conclude that eliminating gang databases entirely could have the unintended consequence of making it more difficult to understand and respond to violence in communities. Instead, we must learn from best practices and improve gang databases by better codifying gang criteria, changing notification rules, contesting designations, and standardizing sunset periods