Identifying People from their Mobile Phone Location Data - is really easy!

Researchers at Massachusetts Institute of Technology (MIT) and the Catholic University of Louvain studied 15 months' worth of anonymised mobile phone records for 1.5 million individuals. Here's the full study.

With no real surprise they found from the "mobility traces" - the evident paths of each mobile phone - that only four locations and times were enough to identify a particular user. We are predictable and so Dan Ariely Work comes true. 

In their own words “They studied fifteen months of human mobility data for one and a half million individuals and find that human mobility traces are highly unique. In fact, in a dataset where the location of an individual is specified hourly, and with a spatial resolution equal to that given by the carrier's antennas, four spatio-temporal points are enough to uniquely identify 95% of the individuals. We coarsen the data spatially and temporally to find a formula for the uniqueness of human mobility traces given their resolution and the available outside information. This formula shows that the uniqueness of mobility traces decays approximately as the 1/10 power of their resolution. Hence, even coarse datasets provide little anonymity. These findings represent fundamental constraints to an individual's privacy and have important implications for the design of frameworks and institutions dedicated to protect the privacy of individuals.”

None of this is new as in 1930, Edmond Locard showed that only 12 points are needed to uniquely identify a fingerprint.