In this study we analyze one year of anonymized telecommunications data for over one million customers from a large European cellphone operator, and we investigate the relationship between people's calls and their physical location. We discover that more than 90% of users who have called each other have also shared the same space (cell tower), even if they live far apart. Moreover, we find that close to 70% of users who call each other frequently (at least once per month on average) have shared the same space at the same time -an instance that we call co-location. Co-locations appear indicative of coordination calls, which occur just before face-to-face meetings. Their number is highly predictable based on the amount of calls between two users and the distance between their home locations -suggesting a new way to quantify the interplay between telecommunications and face-to-face interactions.
Firstly, in REF , the authors analyzed one year of mobile telecommunications data and investigated the relationship between people's calls and their physical location.
Interplay between telecommunications and face-to-face interactions - a study using mobile phone data
PLoS ONE 6(7): e20814, 2011
Biology Physics Computer Science Medicine