Drawing on research that has examined small group behavior, this study examined the relationship between the presence of co-offenders and offense severity, focusing on weapon use and victim injury.
Peers influence offending, both directly through co-offending and indirectly through information and advice. Despite such findings, there is limited research into the ways in which the presence of other offenders (i.e., accomplices) may impact criminal behavior, especially violence. The current research hypothesized that, owing to a diffusion of responsibility and other group processes, crimes committed by groups are more severe than crimes committed by a single offender and that crimes committed by large co-offending groups are particularly severe. This research also proposes that anonymity is an important mechanism behind this relationship and tested the hypothesis that the relationship between groups and offense severity varies according to the victim–offender relationship. Using data from the National Incident-Based Reporting System (NIBRS), the results indicate that (a) offenses committed by groups of offenders are more likely than offenses committed by a single offender to be severe (i.e., involve a weapon, result in injury); (b) as the size of the co-offending group increases, the likelihood of offense severity also increases; and (c) whether the victim is known to the offender is an important predictor of the relationship between co-offending and offense severity. (publisher abstract modified)