In a joint effort between the Yale Department of Sociology and Yale Law School, Professor Andrew Papachristos and Professor Tracey Meares led a workshop on the use of social network analysis in the fields of criminal justice and violence prevention. Workshop attendees included scholars from a variety of academic institutions as well as analysts and officers from the New Haven Police Department, Hartford Police Department, and East Palo Alto Police Department. After an introduction to basic tenets of graph/social network analysis such as centrality, diffusion, contagion, and how those concepts have been applied to fields ranging from public health to business, the workshop turned to how similar techniques can be used in the study and practice of criminal justice. Papachristos, with the assistance of doctoral student Michael Sierra-Arevalo, instructed attendees on how to use administrative data, such as arrest records, to create social network maps that can not only show how offenders are linked to one another, but can also uncover the underlying structure among groups of offenders. Once this structure is brought to light, law enforcement, service providers, and violence prevention experts are better able to design more effective intervention or prevention techniques by targeting either those individuals who are most at risk, or those who are the most “important” individuals within criminal networks.