Do Gang Injunctions Reduce Violent Crime? Four Tests in Merseyside, UK

Abstract

Research QuestionDid gang members and gangs named by police in four separate court-ordered 24-month injunctions, issued at different times, reduce the frequency and harm of crimes they committed, and suffer fewer crimes against themselves as well?DataThe study examined criminal histories of 36 members of four gangs for a 36-month period before and a 36-month period after their respective injunctions. Data also included records of crimes committed against the gang members in the same time periods. Criminal activity was measured by arrests, station interviews, fixed penalty notices and summonses. Days offenders spent in custody, which rose during the gang injunction periods, were removed from denominators calculating rates, so that the estimates of changes in offender behaviour and victimisations are all based on their days at liberty and out of prison or jail.MethodsThe study compared the magnitude of change in both individual-level and gang-level measures of crime and victimisation from before to after the issuance of the injunction as ‘natural quasi-experiments’, with comparisons made to other gangs in Liverpool which had not been subjects of injunctions.FindingsAcross all 36 gang members, their individual offending counts dropped by 70% in the 3 years after their gang injunctions, while the Cambridge Crime Harm Index weight of the seriousness of their total crimes dropped by 61%. Fewer criminal events were attributed to 92% of the individuals in the second 3-year period than in the first, while only 8% increased their detected activity. Taking the four gangs as the unit of analysis, their offences dropped by 74% in the 3 years after the injunctions, while their Crime Harm Index weight dropped by 70%. Victimisation of the gang members in their 3-year post-injunction period dropped by 60% compared to the pre-injunction period. Comparisons between gangs with injunctions and gangs without showed downward crime trends in the injunction gangs that were not observed in the comparisons during the same time periods, but regression to the mean could not be ruled out as an explanation for the findings.ConclusionsThe evidence for the effectiveness of gang injunctions in reducing crime harm is stronger than the evidence for most police practices. There is no evidence in this study of these injunctions causing crime to increase. Police agencies may be encouraged to use such powers when available, as long as they track the trends with sufficient care to detect any potential backfire effects.