Over the holiday period, the physics arxiv blog is re-running the most popular blogs (by page views) of 2007.<\/p>\n
Cellphone records reveal new patterns of human activity<\/a>
\n29 October<\/p>\nSwitch yer mobile phone on and it checks into the local network giving your location and the time you were there. The network also records the calls you make, their frequency, duration and to whom you make them plus wherever they happen to be too.<\/p><\/blockquote>\n
Multiply that by the entire popualtion (mobile phone penetration approaches 100 per cent in many western countries) and you\u2019ve got a data set that can give an unprecedented insight into the links between people and the way they move and behave.<\/p>\n
Albert-Laszlo \u201cBar\u201d Barabasi at Northeastern University in Boston and a few pals have been a-grindin\u2019 and a-crunchin\u2019 the data from several million cellphones and are now revealing what they\u2019ve found.<\/p>\n
Turns out the data can be used to identify friends and family (from the frequency and duration of calls and whether they are reciprocated), they can show how social groups evolve and how they fall apart.<\/p>\n
The data can also suggests how to monitor the way people behave in emergencies in realtime. For example, a pile up on the freeway causes lots of rapidly moving phones grind to a halt, a few call the emergency services while others call the office\/spouse\/lovers. Spot that pattern and its a pretty good indication that an event has occurred. Location information might even help to determine exactly where the accident took place.<\/p>\n
Barbara Rasi has also found previously unknown patterns in human behaviour. For example, although the number of people making calls varies hugely during the day and night, the percentage who are on the move (ie who make consecutive calls from different lcoations) is always roughly the same. And the average distance they travel between calls in a half hour period is also stable at about 6 km. He says this is just the beginning of what will be possible with this kind of data.<\/p>\n
What ya\u2019ll want to know is how anonymous is it? The message is: Big Brother is watching\u2026but he only has access to anonymized data.<\/p>\n
But ah don\u2019t buy it. It wasn\u2019t so long ago that the raw data from search engines was thought to be anonymised if a person\u2019s name was removed from it. But that myth was exploded by journalists from the New York Times who tracked down one individual using only her AOL search records<\/a>.<\/p>\n
How long before we see a similar expose with supposedly anonymized mobile phone records?<\/p>\n