Researchers in the USA have shown that it’s possible to identify friendships by looking at mobile phone call records and the proximity of users. They gave 94 people modified Nokia 6600 handsets that tracked communication, users’ locations and their proximity to other users.
The results from this five-year study, which have been published in Proceedings of the National Academy of Sciences, showed that the data could be used with 95% accuracy to predict whether two people were friends. In addition, the phone mobile data could also indicate the volunteers' satisfaction at work: those who said they were less satisfied with their jobs were less likely to have friends nearby and more likely to call their friends during work hours.