It sounds like something out of a science fiction novel: Police arrive on a crime scene before the crime has even happened, alerted by a computer, trying to stop it from taking place.

But it's not science fiction. It's a reality, and it's called PredPol -- Predictive Policing.

How It Works

Essentially, it's done with computers that collect and analyze data. They crunch the numbers and figure out when and where crime is most likely. Police can then head to those locations. They may know the type of crime -- theft, for instance -- that's likely to occur, and they'll be on the lookout.

The system basically just figures out trends: Where crimes happen, what types and at what times. It then puts red boxes on a map and tells officers what's most likely to occur.

Does It Work?

Some officers believe that it absolutely works. They told a story about PredPol saying a car theft was probably going to happen at a specific location. They went there, and, sure enough, discovered a stolen car with the suspect inside. He ran. They couldn't catch him, but PredPol gave them another location where a car theft was probable. They went there and found yet another stolen car. The exact same suspect was inside.


The system does raise questions, though. If the data is skewed -- perhaps it's biased against minorities, for instance -- does that mean the system will then be biased? If police have been warned that a crime is about to happen, would they then treat innocent people as criminals upon arrival, despite having no other reason to think they did anything wrong?

Criminal Defense

Some researchers have called this system a "Holy Grail" for police officers, but it is controversial. Those who are arrested must be sure they know their legal defense options and their rights.