Social agents in charge of the coordination of local security committees dedicated to delinquency and its prevention seem to integrate submissvely the tools offered by the “new criminology” (such as local observatories, statistics, mapping, population profiling). In reality, such tools are mobilised for various reasons that are not only geared towards efficiency. The agents in charge not only use quantitative techniques because they believe in their legitimacy. They also use them as a way to consolidate the legitimacy of their roles. These roles are indeed quite new in the security landscape in France, and mobilising such criminological tools enable the agents to claim a particular form of expertise.