1. Forecasting crime
In 2011, police in Los Angeles and Manchester ran radical trials. They used a computer algorithm to try to predict where crime would occur before it happened.
That might sound like science fiction, but the police wanted to test if by analysing large amounts of crime data, also known as 'big data', they could spot patterns in the way criminals behaved. Then they'd deploy their resources in the areas the computer predicted crime would strike.
Policing to prevent crime is nothing new. In Britain, it goes back hundreds of years. But if using big data worked, it would mean humans taking advice on where to police from a machine rather than relying on their own experience.
3. Does it work?
The 2011 trial in LA was a success, with a significant fall in property crime and burglaries. The LAPD Foothill Division has continued to use predictive software.
Trials have taken place across the UK, from Kent to Yorkshire. The results suggest that predictive policing models can help cut crimes where perpetrators exhibit predictable patterns of behaviour. In 2011, for example, in Trafford, Manchester, police noted a 26.6% fall in burglaries, compared to a 9.8% fall across Greater Manchester in the same period.
However, Kent Police had a slightly less straightforward experience. It ran a successful four-month trial starting in December 2012, but after rolling out predictive policing across the county in April 2013, recorded an increase in crime for the following year. It blamed the rise on a failure to deploy resources effectively and inaccurate crime data.
Rachel Tuffin, director of research at the College of Policing, says there is a strong interest in the potential of predictive policing, but further trials are needed. She explains: "Research shows predictive analysis can identify hotspots more accurately, and separate studies show targeting police patrol and problem-solving in hotspots can reduce crime. Forces in the UK and US are testing the effect of combining prediction with action to remove the causes of crime."
4. Ethical dilemmas
Predictive policing promises a new era of law enforcement. But some critics are concerned it may lead to an erosion of civil liberties.