Effects of suspensions on offences and damage of suspended offenders and their peers on an online chat platform

•We analyzed 263,491 Pigg Party users, 182,227 offences, and 12,780 suspensions.•Suspensions decreased offence risks of suspended offenders and their peers.•Suspensions decreased damage risks of suspended offenders and their peers.•Permanent suspension decreased offence risks for popular suspended offenders.•Popularity was a negative mediator of suspension effect on offenders’ offence risk.•Popularity was a positive mediator of suspension effect on their peers’ offence risk. While suspensions of online chat offenders occur regularly, it is not known whether the suspensions reduce future offences by them and their peers. Our study aims to clarify the effects of suspensions using a simulation network model on Pigg Party, a popular Japanese online chat platform that uses avatars and has private, group, and public chat channels. The participants were 263,491 Pigg Party users. Data were collected over six months and involved 182,227 offences and 12,780 suspensions. We estimated the offence/damage probabilities and latencies of offences/damage after suspension in both the actual and simulation networks. The results showed that all suspensions, including 24-h, 48-h and permanent suspensions, decreased the risk of offence of offenders and their peers after suspension. Furthermore, these suspensions also decreased the damage of offenders and their peers after suspension. In particular, permanent suspension was effective in reducing the offence and damage risks of popular offenders and their peers. Online suspensions were effective in decreasing future offenses and damage by suspended offenders and their peers. Permanent suspensions may be required for popular offender groups.