A study was conducted in Stanford University to examine the impact on privacy of the National Security Agency’s collection of bulk telephone metadata nationwide. The study found that telephone metadata is densely interconnected, can trivially be reidentified, enables automated location and relationship inferences, and can be used to determine highly sensitive traits.
The authors conclude that more broadly, this project emphasizes the need for scientifically rigorous surveillance regulation. Much of the law and policy that we explored in this research was informed by assumption and conventional wisdom, not quantitative analysis. To strike an appropriate balance between national security and civil liberties, future policymaking must be informed by input from the relevant sciences.