A picture of how wealthy or poor people are can be reconstructed from anonymized data generated by mobile phones, according to researchers analyzing cell phone data from Rwanda.
Personal information that mobile devices gather such as a person’s location often gets anonymized by stripping it of names, home addresses, phone numbers, and other obvious identifying details. Such metadata often get shared, and underlies popular services such as Google’s real-time monitoring of road traffic.
However, anonymized data can still divulge a great deal about individuals, suggesting that the process does not protect privacy as well as often thought. For instance, anonymized credit card data can easily be used to identify credit card users, and analyzing the movements of your social contacts can help generate a relatively complete picture of your movements.