Their key finding was that the total number of mutual friends two people share — embeddedness, in social networking terms — is actually a fairly weak indicator of romantic relationships. Far better, they found, was a network measure that they call dispersion. This yardstick measures mutual friends, but also friends from the further-flung reaches of a person’s network neighborhood. High dispersion occurs when a couple’s mutual friends are not well connected to one another.
Adrianne Jeffries explains further:
The researchers were able to identify who was dating whom with 60 percent accuracy, much better than the 2 percent accuracy they’d get from random guessing. High dispersion also seems to be correlated with longer relationships. The study found that couples were 50 percent more likely to break up in the next two months if the dispersion algorithm failed to guess that they were dating.
The scientists also looked at metrics such as how many times a user viewed another’s profile, attendance at the same events, and messages sent. Dispersion turned out to be the most overall accurate metric for determining romantic relationships. The researchers used multiple sets of anonymous data, including a large data set from 1.3 million Facebook users.