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This Data-Driven Tool May Be Able To Prevent Crimes

Zurich has adopted a system that feeds past criminal information into an algorithm that can help predict when and where crimes will occur. Early indications are that it may actually be reducing crime rates.

Precobs, looking at past crimes to predict future ones
Precobs, looking at past crimes to predict future ones

ZURICH — Predicting what crimes will be committed at any given location is a special power any police department would dream about. For the past year, officers in Zurich, among other select cities, have had a tool that aims at just such a power: It's a software called Precobs (Pre Crime Observation System). Using it in select locations in the Swiss city, criminal activity was reduced by 30%, according to police results published last week.

But plenty of experts in criminal science caution that such a tool is still far from being a panacea for crime, due to its lack of serious validation.

Its name, Precobs, sounds an awful lot like “Precogs,” those special beings in Steven Spielberg's 2002 Minority Report (based on the Philip K. Dick short story of the same name) who have premonitions of offenses to come; the inventors of this system, at the German Technical Institute for Prevision by Modelizing of Oberhausen, admit they were inspired by the movie. But their product is far from science fiction.

A variety of data is fed into this computer system: type of offense, place, date, aim of the crime, means used. The information was gathered over a five-year period — which requires a well-organized database. Statistical algorithms are then applied and show the probability of a criminal offense in a 250-meter radius around a target, and in a seven-day interval.

Martin Killias, a criminologist of the University of Zurich, explains that one of the central principles used in these algorithms is the “near repeat.”

“Beginning in the 1980s, statistical research in geography showed the chances are high that another crime will happen close to a previous one,” Killias said.

Zurich police spokesman Marco Cortesi told SRF (Swiss Radio and Television) that, like a mushroom picker who's found a good spot for his collecting returns to it regularly, criminals know the urban areas in which they operate very well: the back alleys that will allow them to escape, the police precincts to avoid, and so on. Changing the nature of these locations forces them to become reacquainted with them, and this has a cost to the would-be criminal.

Press a button?

“The idea is to make the system look in the data for specific models of chains of events that happened in the past to predict, according to the latest crime, what will happen,” says Michael Schweer, the inventor of Precobs. He adds that the algorithms are sharpened with inputs from various sciences including urban topography and criminal psychology.

The Geneva police forces have been trying to predict crimes by cross-checking various parameters of a database for years. “We do it every week, in a ‘human way,’ with satisfaction,” says Jean-Philippe Brandt, the spokesperson.

Schweer says that his system can carry out analyses of data rapidly "in a way no human can in reasonable time.” But he knows his system comes up against growing concern around surveillance, including from news sources beyond police registers, such as social networks.

Other similar systems have been developed, including in the U.S. and the U.K., and their efficiency has been praised. Several German cities are also interested in Precobs, as well as Swiss localities, in the Aargau and Basel-Landschaft cantons, where the system is being tested.

Still, criminologist Martin Killias remains skeptical. He notes the commercial aspect of these products that are sold for several thousands of euros. “The problem is that no real validation meta-analysis of these systems has been carried out. This is because police departments aren’t very open about their work being evaluated,” he says.

Experts say it is ultimately difficult to precisely quantify how much the decrease in criminality can be attributed to any one factor. For Olivier Ribaux, a professor in criminal science at the University of Lausanne, these tools are based on elements of truth in terms of methodology. However, alone, they’re insufficient because they’re part of an efficient whole that stems from different anti-crime policies. "It’s a mistake to think that we now have a "push-the-button" technology to stop criminality," he said. "But that's the exaggerated message we sometimes see.”

Schweer, nevertheless, is optimistic about the future of his crime fighting method: “In ten years’ time, these predictive technologies will be an essential part of police departments all over Europe,” he said.

Not everyone is on board, however. After having tried it, another law enforcement office in Zurich — the canton police — opted not to acquire the Precobs package. Canton police spokesperson Beat Jost said, “It didn’t correspond to our needs, to our wide territory and the various types of offenses we deal with."

The jury, even in Zurich alone, is still out.

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