To make advertising pay as audiences move over to mobile devices, Drawbridge is using statistical methods that rely on anonymous data to track people as they move between their smartphones, tablets, and PCs, MIT Technology Review reports.

Drawbridge works by looking at the cookie data that comes with a request from a mobile or desktop browser or app to an ad exchange, and using its “bridging” algorithm to assess the probability that any two arbitrary cookies from different devices are associated with the same person.

Unlike a method known as device fingerprinting, Drawbridge doesn’t rely on technologies that directly track user activity, or report geolocation or other invasive device identifiers, the company says.