The Links of Love
de Facebook Data Team, el Martes, 14 de febrero de 2012
Some people marry their high school sweethearts and live together ‘til death do them part’. Other couples go their separate ways and find love anew. All these collective romantic movements can be used to construct a relationship graph. Relationship graphs (Susan dated Joe who previously dated Jane...) are difficult to maintain on a napkin or a whiteboard because who’s dating whom can quickly become yesterday’s news. But on Facebook, updating a relationship status is as easy as a couple of clicks.
As Valentine’s Day approached, we wondered just how large the Facebook relationship graph might be. So we looked at the romances and splits among people on the site over the past three years.
Since 2009, more than 260 million Facebook users worldwide listed themselves as being “in a relationship” with another person on Facebook. Of these, 65% noted just one person they were in a relationship with. But it is those who dated more than one person who help connect the relationship graph.
When we connect people through their relationship statuses, we find 85 million individuals (32%) are in one giant component, connecting people across the globe. This means that by following the relationship ties from any one person within the component you can reach any other person through relationship ties. For example, if Amy dated Bob who dated Cathy who dated David, then Amy and David are connected.
But before we can conclude that a large part of world is extensively romantically linked, we should note that not everyone uses Facebook's relationship feature to indicate a romantic relationship. Often young women specify that they are “in a relationship” with their BFFs (“best friend forever”). Roughly 20% of all relationships for the 15-and-under crowd are between girls. This number dips to 15% for 18-year-olds and is just 7% for 25-year-olds. With this in mind, we temporarily omitted those ties from our analysis to recalculate the giant component and found the component to still to be 45.4 million individuals strong.
So what exactly does this network look like? It’s difficult to visualize such a large network in its entirety, but we can explore a sliver of it as an example, focusing on US users who were over 18 at the start of the relationship.
We picked a random person, and then picked one person they were in a relationship with. Next we picked someone that the second person had been in a relationship with and so on. Stepping through the network in this manner, we saw long chains of affection.
Visually, we can see that the network is not tightly clustered. In fact, the average of the shortest number of steps to get from any one U.S. user to any other individual is 16.7. This is much higher than the 4.74 steps you’d need to go from any Facebook user to another through friendship, as opposed to romantic, ties.
But remember – we’re only looking at the past three years of data, making our relationship graph quite young. As more relationships blossom, the relationship graph is bound to fill in with new romantic ties. Good luck creating (or reinforcing) one of your own this Valentine’s Day.