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Internet, Social Media

Structural diversity in social contagion: Studying Facebook


The social networking site Facebook is fast approaching 1 billion users, but there are still 6 billion people who have not joined the site and only about 360 million of Facebook’s 860 million registered users visit the site at least six days a week. Research has found that 20% to 30% of those on Facebook are “power users” who are much more active on the site than the average user. Who is likely to join Facebook and actively engage on the site once they’ve joined?

A 2012 study by Cornell University and Facebook published in the Proceedings of the National Academy of Sciences, “Structural Diversity in Social Contagion,” identifies Facebook recruitment and engagement patterns by examining the interconnectedness of a user’s friends on Facebook both before and after that person joins. The researchers studied approximately 10 million Facebook users who signed up during 2010 and had cultivated friend “neighborhoods” consisting of 10, 20, 30, 40, or 50 friends one week after registration and who were actively engaged on the site three months after joining.

The study’s findings include:

  • A person is much more likely to join Facebook if that person has friends on Facebook who do not know each other — a structurally diverse network — than if that person’s friends are all connected on the site. “The number of distinct social contexts represented on Facebook … predicts the probability of joining.”
  • An invitation to join Facebook that listed four unrelated site users sent to a potential user was more than twice as likely to prompt the individual to join than an invitation that listed four connected users. “It is not the number of people who have invited you, nor the number of links among them, but instead the number of connected components they form that captures your probability of accepting the invitation.”
  • Once a user joins Facebook, the structural diversity of his or her network also impacts the level of engagement: more active Facebook users have friends on the site spanning numerous social circles. “Simply counting connected components leads to a muddled view of predicted engagement…. However, extending the notion of diversity according to any of the definitions above suffices to provide positive predictors of future long-term engagement.”

The researchers conclude that “these findings suggest an alternate perspective for recruitment to political causes, the promotion of health practices and marketing; to convince individuals to change their behavior, it may be less important that they receive many endorsements than that they receive the message from multiple directions.”

Tags: Facebook

    Writer: | Last updated: April 30, 2012

    Citation: Ugander, Johan; Backstrom, Lars; Marlow, Cameron; Kleinberg, Jon. "Structural Diversity in Social Contagion," Proceedings of the National Academy of Sciences of the United States of America, April 17, 2012, Vol. 109, No. 16, 5962-5966. doi: 10.1073/pnas.1116502109.

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    Analysis assignments

    Read the issue-related Wired Science article titled "How Facebook Contagion Spreads."

    1. What key insights from the study and article should reporters be aware of as they cover issues relating to online social networking site behaviors?

    Read the full study titled "Structural Diversity in Social Contagion."

    1. What are the study's key technical term(s)? Which ones need to be put into language a lay audience can understand?
    2. Do the study’s authors put the research into context and show how they are advancing the state of knowledge about the subject? If so, what did the previous research indicate?
    3. What is the study’s research method? If there are statistical results, how did the scholars arrive at them?
    4. Evaluate the study's limitations. (For example, are there weaknesses in the study's data or research design?)
    5. How could the findings be misreported or misinterpreted by a reporter? In other words, what are the difficulties in conveying the data accurately? Give an example of a faulty headline or story lead.

    Newswriting and digital reporting assignments

    1. Write a lead, headline or nut graph based on the study.
    2. Spend 60 minutes exploring the issue by accessing sources of information other than the study. Write a lead (or headline or nut graph) based on the study but informed by the new information. Does the new information significantly change what one would write based on the study alone?
    3. Compose two Twitter messages of 140 characters or fewer accurately conveying the study’s findings to a general audience. Make sure to use appropriate hashtags.
    4. Choose several key quotations from the study and show how they would be set up and used in a brief blog post.
    5. Map out the structure for a 60-second video segment about the study. What combination of study findings and visual aids could be used?
    6. Find pictures and graphics that might run with a story about the study. If appropriate, also find two related videos to embed in an online posting. Be sure to evaluate the credibility and appropriateness of any materials you would aggregate and repurpose.

    Class discussion questions

    1. What is the study’s most important finding?
    2. Would members of the public intuitively understand the study’s findings? If not, what would be the most effective way to relate them?
    3. What kinds of knowledgeable sources you would interview to report the study in context?
    4. How could the study be “localized” and shown to have community implications?
    5. How might the study be explained through the stories of representative individuals? What kinds of people might a reporter feature to make such a story about the study come alive?
    6. What sorts of stories might be generated out of secondary information or ideas discussed in the study?