Tracking Violent Crime with Ambulance Data: How Much Crime Goes Uncounted?

Research Question What proportion of ambulance records documenting injuries caused by criminal violence is included in police records for violent crimes occurring in the same area at the same dates and times as incidents found in ambulance records? Data We analysed subsets of three datasets during matched time periods: West Midlands Ambulance Service records of all 36,639 incidents of violent injuries from January 2012 to March 2017; 132,317 West Midlands Police records of violent crimes from January 2012 to December 2015; and 9083 records of treatment of violent injuries as recorded in hospital Emergency Department (ED) records covering September 2013 to March 2016. Methods We compared all incidents in the ambulance dataset and ED data to corresponding locations and times in incidents recorded in police datasets. Findings Approximately 90% of cases in the ambulance dataset did not have a corresponding case in the police dataset. The proportion was even lower in the Emergency Department dataset, where less than 5% of cases were successfully matched to a police record. These data suggest that adding the medical data to the police data could add 15 to 20% more violent offences to the totals recorded by the police. Conclusions Tracking identified ambulance data can add substantial numbers of serious violent crimes, over and above those reported to the police. These added cases can increase the targeting of police and public health resources to prevent harm against victims, at places, and by offenders at highest risk of serious violence.