The NSA has been using its collections of data since November 2010 to create sophisticated graphs of some Americans’ social connections that can identify their associates, their locations at certain times, their traveling companions and other personal information, a New York Times article reports.

The agency is using the analysis of phone calls and email logs to examine Americans’ networks of associations for foreign intelligence purposes, and the shift in policy was intended to help the agency “discover and track” connections between intelligence targets overseas and people in the U.S.

According to the article, the NSA was authorized to conduct “large-scale graph analysis on very large sets of communications metadata without having to check foreignness” of every email address, phone number or other identifier. This sort of data analysis had previously been permitted only for foreigners. The agency can augment the metadata with public, commercial or other data, including bank codes, insurance information, Facebook profiles, passenger manifests, voter registration rolls and GPS location information, as well a property records and unspecified tax data.