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Study Secretly Tracks Cell Phone Users

Posted on: Thursday, 5 June 2008, 11:15 CDT

New research that involved the tracking of more than 100,000 mobile phone users is shedding light on the way humans live.

Researchers involved with the study said their findings would be useful in city planning and preparing for emergencies.
 
"Despite the diversity of their travel history, humans follow simple reproducible patterns," Albert-Laszlo Barabasi of Northeastern University in Boston and colleagues wrote in their report.

Published in the journal Nature, the report showed that people move less than 20 miles on a regular basis and tend to live through a series of surprisingly predictable patterns.

Previous studies had attempted to track human activity through GPS or surveys, but it was expensive.

One study used information collected from the Web site wheresgeorge.com, which allows anyone to track a dollar bill as it circulates through the economy. The site has so far tracked nearly 130 million notes.

These previous studies determined that humans wander randomly, similar to a so-called “Levy flight” pattern displayed by many foraging animals.

But researchers from Northeastern University with the recent study say that human activity can’t be completely defined through tracking their monetary transactions.

"The bills pass from one person to another so they can't measure individual behavior," Gonzalez said.

The study found that nearly half of the people in the study pretty much keep to a circle little more than six miles wide and that 83 percent of the people tracked mostly stay within a 37-mile wide circle.

However, one controversial issue about the study is that it tracked the movements of 100,000 cell phone users without their permission, which would be illegal in the United States.

The scientists would not disclose where the study took place, only describing the location as an industrialized nation.

Each time a participant made or received a call or text message, the location of the mobile base station relaying the data was recorded.

Information was collected for six months. But, according to the researchers, a person's pattern of movement could be seen in just three.

In a second set of records, researchers took another 206 cell phones that had tracking devices in them and got records for their locations every two hours over a week's time period.

Study co-author Cesar Hidalgo, a physics researcher at Northeastern, said he and his colleagues didn't know the individual phone numbers because they were disguised into "ugly" 26-digit-and-letter codes.

“This is a new step for science," said study co-author Albert-Lazlo Barabasi, director of Northeastern's Center for Complex Network Research. "For the first time we have a chance to really objectively follow certain aspects of human behavior."

Barabasi said he spent nearly half his time on the study worrying about privacy issues. They were not able to say precisely where people were, just which nearby cell phone tower was relaying the calls, which could be a matter of blocks or miles.

But Arthur Caplan at the University of Pennsylvania said: "There is plenty going on here that sets off ethical alarm bells about privacy and trustworthiness.”

Studies done on normal behavior at public places is "fair game for researchers" as long as no one can figure out identities, he added.

"So if I fight at a soccer match or walk through 30th Street train station in Philly, I can be studied," Caplan wrote. "But my cell phone is not public. My cell phone is personal. Tracking it and thus its owner is an active intrusion into personal privacy."

But Hidalgo insists that there are many great benefits from his team’s research.

"In the wrong hands the data could be misused," Hidalgo said. "But in scientists' hands you're trying to look at broad patterns.... We're not trying to do evil things. We're trying to make the world a little better."

Dr Marta Gonzalez of Northeastern University, Boston, US, said there is even more to learn from this area of research.

"It would be wonderful if every [mobile] carrier could give universities access to their data because it's so rich," said Gonzalez, one of the authors of the paper.

Dr William Webb, head of research and development at the UK telecoms regulator, Ofcom, agreed that mobile phone data was still underexploited.

"This is just the tip of the iceberg," he said.

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On the Net:

http://www.nature.com/nature

Source: redOrbit staff and wire reports

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