The importance of studying co-offending networks for criminological theory and policy

For nearly a century, criminologists have been well acquainted with the group nature of crime. In the early part of the twentieth century, Shaw and McKay (1942) observed that the vast majority (approximately 80%) of juveniles who were seen in the Cook County Juvenile Court were suspected of committing crimes with accomplices; similar findings have consistently emerged in the decades since with regard to both official records and self-reports, as well as across a wide range of locations (e.g., Carrington, 2002; Sarnecki, 2001; Warr, 2002; cf. Stolzenberg & D’Allesio, 2008). Indeed, Breckinridge and Abbott’s (1912) observation that a delinquent who offends alone is a rarity can, at this point, rightly be called a criminological “fact” (McGloin, Sullivan, Piquero, & Bacon, 2008).