Facebook data scientists can figure out who you're sleeping with, even if your relationship isn't "Facebook official," and in a new paper researchers explain how they figured out the method, the Atlantic reports. Turns out the key is to look at more than just mutual friends. "Embeddedness," or the number of mutual friends two people have, can show how close those people are (the more mutual friends, the closer they are). But researchers found embeddedness predicted the correct significant others just 24.7% of the time. A more accurate predictor is something called "dispersion."
That means researchers looked at how many networks were shared between two people, working on the theory that your romantic partner will have met your family and your current friends and co-workers, as well as old friends from high school or college. By looking at which friend was the most dispersed across all of a Facebook user's networks, researchers upped their accuracy at predicting significant others to 50%. "A spouse or romantic partner is a bridge between a person’s different social worlds," one researcher explains, according to the New York Times. Oh, and dispersion also works to predict the health of your relationship: The more dispersion a user had with his or her partner, the more likely the relationship was to last at least 60 days.