Police should concentrate on crimes that cause “damage to victims” rather than trying to meet headline-grabbing targets to reduce the overall rate, a new study said.
Currently police are following a Victorian model presenting crime in “grand totals” that give equal weight to shoplifting and murder.
Yet University of Cambridge criminologists argue these league tables and the need to show “crime is down” results in police forces focusing on minor yet high-volume offences that cause less harm than rarer but more serious crimes.
It was failing to pick up those crimes that caused the most societal harm.
Instead they should follow a “menu of harm” that measures crime according to the price of damage inflicted on victims - rather than counting crimes as if they are all of equal seriousness.
This would refocus police attention and resources on the worst criminal acts, detect crime “harm spots” similar to “crime hotspots,” as well as the most dangerous repeat offenders who often fail to be picked up under the present system.
This targeted policing could, in turn, reduce prison populations.
Cambridge Institute of Criminology Director Professor Lawrence Sherman and former Chief Constable Peter Neyroud have devised the Cambridge Crime Harm Index (CHI).
It is essentially a crime version of the cost-of-living index - a classification system weighted by, in this case, the likely impact of an offence on victims.
Prof Sherman said: “Not all crimes are created equal. Counting them as if they are fosters distortion of risk and accountability.
“If shoplifting drops while murder triples, crime is reported as ‘down’ - yet any common sense view of public safety cries out for some adjustment for seriousness.”
He added the new system was simple and required no extra funding and was based on sentencing guidelines and numbers of ‘imprisonable’ days.
The study compared crime across the UK over ten years using the current and news system
While overall crime counts between 2002 and 2012 showed a drop of 37 per cent, the harm index reveals that this is an overestimation in terms of public safety, as imprisonable days reflecting ‘harm caused’ only dropped 21 per cent.
For example the Cambridge CHI helped Sussex Constabulary map patterns of domestic violence to reveal of the 25,000 couples coming to police attention over six years, resulting in some 36,000 callouts - fewer than 2 per cent of couples generated 80 per cent of all harm to each other.
Adding the CHI to the current system helps improve understanding of what the crime counts really mean.
Prof Sherman said: “Currently, there is no meaningful ‘bottom line’ indicator of whether public safety is actually improving or declining in any given year or place.
“Measuring by the number of days in prison each crime could attract ensures that police, policy makers and the public are better informed on rates and trends of crime, the risks posed and resources required.”
But he added any new approach to measuring crime must pass a three-pronged test of cost, reliability and democracy “reflecting the will of the people.”
The study was published in the journal Policing.