Facebook is making the world even smaller
A study examining 69 billion friendships on Facebook shows the average degrees of separation between two randomly chosen users to be 3.74
Facebook has conducted a joint study which suggests that there are on average 3.74 degrees of separation between users on the popular social networking website. The study, joint between Facebook’s data scientist Lars Backstrom and four researchers from the University of Milan, found that the number of people that link two others on average is approximately four. That is, as the authors of the study explain, “when considering another person in the world, a friend of your friend knows a friend of their friend.”
The study was carried out in May before the ‘Subscriptions’ feature was added to Facebook and celebrity fan ‘Pages’ were not taken into account in the data. All active members of the site were included in the study, and users were deemed to be such if they had logged on at least once over a 28 day period. This marks the largest test regarding Hungarian author Frigyes Karinthy’s idea that there were six degrees of separation between any two people on Earth. The hypothesis has long since been tested with various samples, including a notable effort by psychologist Stanley Milgram in the 1960s involving delivering a letter to an arbitrary person by passing through acquaintances.
There are on average 3.74 degrees of separation between users on Facebook
Facebook’s social graph data had 721 million members at the time of the experiment, with a total of 69 billion friendships. The researchers were able to analyse the data using rules from graph theory within discrete mathematics and by performing combinatorical analysis. They used a 24-core computer with a 1 Terabyte (TB) hard disk to crunch the numbers, costing them “no more than a couple of thousand pounds”.
Facebook typically limits users to a maximum cap of 5,000 friends. The median amount from the sample size representative of 10% of the global population was only 100 friends, accounting for 0.000014% of Facebook’s total membership. Results indicated 99.6% of all pairs of users were connected by 5 degrees of separation, with 92% connected with only four. The average distance between any two users was found to be 3.74 degrees, shorter than the average distance of 4.28 found by a similar Facebook study in 2008, strengthening the idea that a larger sample size often results in a lower separation level.
The researchers said that “the average distance appears to be stabilising”, suggesting it would not change from 3.74 even if the rest of the world joined Facebook.
