Mobile phones make it easy to accurately predict human movement patterns

(Val Thoermer)

A new report that tracked mobile phone users' locations showed that our everyday movements can be predicted up to 93 percent of the time.

The February 19 report, entitled "Limits of Predictability in Human Mobility," milled data obtained from cellular service providers to discover mobile users' everyday travel routines. The study found that 93 percent of the time, humans would follow the same travel routines. Their mobile phone location pinpointed them visiting the same places on a regular basis - travelling back and forth between the destinations week in, week out.

Knowing this, the authors of the study noted that the location-based information could be used for a range of different applications from "predicting the spread of human and electronic viruses to city planning and resource management in mobile communications."

The location-based information was obtained by using information normally collected by cell phone companies. When a customer makes a call, it is usually directed through the nearest cell tower; this provides network providers with a relatively accurate indication of their customers' exact location when a call is placed.

"The authors analyzed various aspects of the information related to the calls, as well as information that could be aggregated over multiple calls: number of distinct locations, historical probability that the location had been visited in the past, time spent at each tower, the order in which customers usually visited towers, and so on. With these numbers, the authors could create measures of the entropy of the customers' trajectories," explained Ars Technica on February 23 who wrote an article based on the findings published in Science.

Despite a large range of travel distances covered by people that were tracked, the report found that humans' travel patterns were almost all equally predictable. Cell phone users were most likely to travel in the same direction and to the same places regardless of if they were confined to a six-mile radius (like most callers) or jet-setted around the world.

Users' locations during work hours were the most easy to predict. Humans showed the most irregular travel patterns could be seen during the hours before work, during lunch or after work, however, even these were predictable. Ars Technica noted that there was a 70 percent chance that mobile phone users would be at their most-visited location at any one random point in time.

http://www.sciencemag.org/cgi/content/abstract/327/5968/1018

http://arstechnica.com/science/news/2010/02/cell-phones-show-human-movement-predictable-93-of-the-time.ars