“Offending with the accomplices of my accomplices”: Evidence and implications regarding triadic closure in co-offending networks

Abstract

We measured triadic closure in co-offending networks – i.e., the tendency of two individuals to co-offend if they share an accomplice – using a method that addresses the risk of overestimating clustering coefficients when using one-mode projections. We also assess the statistical significance of clustering coefficients using null models. The data relates to adult offenders (N = 274,689) connected to criminal investigations (N = 286,591) in Colombia. The observed coefficients range between 0.05 and 0.53 and are statistically significant, indicating that accomplices become sources of information about potential associates. They support the idea of preventing crime by targeting offenders’ trustworthiness and disrupting information flows.