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Social network analysis course 2010 - 2011


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the 5th social media course at skema business school about social network analysis

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Social network analysis course 2010 - 2011

  1. 1. Social Network Analysis Guillaume ERETEO
  2. 2. Social Networks A social network is made of actors (people, organizations, group) that are tied by social links.
  3. 3. Sociograms and graphs actors are represented by points (nodes, vertices) and relations by lines (edges, links, arcs)
  4. 4. • explicit and declared relations • interactions between actors • affiliation between actors Social links colleague communicate like like web
  5. 5. undirected networks well suited for representing network with symmetric relationships such as facebook
  6. 6. directed networks well suited for representing network with non reciprocal relationships such as Twitter
  7. 7. weighted networks well suited for representing the intensity of relationships, the number of interactions (e.g. mails), or the number of affiliations (e.g. shared links). 1 0.5 1 2 3
  8. 8. labelled networks well suited for representing the type of relationships family colleague father friend follow follow father
  9. 9. Social network analysis helps understanding and exploiting the key features of social networks in order to manage their assets, their life cycle and predict their evolution.
  10. 10. What for? • To control information flow • To foster communication • To improve network resilience • To trust or not
  11. 11. Diameter the maximum distance between two actors
  12. 12. Density of links indicates the cohesion of the network
  13. 13. community detection distribution of actors and activities
  14. 14. community membership • influences the way information is shared • influences the way actors behave
  15. 15. Centrality: strategic positions degree centrality focuses on the number of relations: reveal local popularity [Freeman 1979]
  16. 16. Centrality: strategic positions closeness centrality focuses on the proximity of actors: reveal capacity to communicate [Freeman 1979]
  17. 17. Centrality: strategic positions beetweenness centrality focuses on intermediary actors reveals brokers and privileged actor in the information flow [Freeman 1979] "A place for good ideas" [Burt 1992] [Burt 2004]
  18. 18. Centrality: strategic positions eigen vector centrality focuses on the connections of neighbours reveals actors that are well connected
  19. 19. transitivity of relationships evaluating social opportunities Peter Jack Paul
  20. 20. tendency to bind with similar others "Birds of a feather flock together" "interaction produces similarity, while similarity produces interaction" [Mika 2005]
  21. 21. Preferential attachement
  22. 22. who will increase its popularity?
  23. 23. Balance Theory [Heider 1958]
  24. 24. Critical mass
  25. 25. Many ways of connecting people! likes ingredient typemainDish Food subclassOf type
  26. 26. Who has the best betweeness? this is a matter of semantic knows in passing has met colleague works With works With friend
  27. 27. Metrics are not sufficient enough knows in passing has met colleague works With works With friend
  28. 28. examples of vizualisation and analysis tools
  29. 29. Touchgraph facebook browser easily vizualize your facebook social network
  30. 30. this is mine
  31. 31. Analyze your facebook network 1. Extract it first with netvizz: http:// 2. Open it with my favorite graph visualization tool: Gephi http://
  32. 32. extract with Netvizz • choose the information to include • Save the file
  33. 33. analyze with Gephi
  34. 34. Your network is undirected
  35. 35. select the force layout
  36. 36. detect communities
  37. 37. highlight communities
  38. 38. compute shortest paths of relations
  39. 39. highlight most popular actors
  40. 40. Highlight brokers
  41. 41. print attributes
  42. 42. NODEXL • Excel 2007 based social network visualization and analysis tool • Homepage • Tutorial
  43. 43. Quick overview of the tutorial
  44. 44. "One way to begin using NodeXL is to type in your own edge list. For example, you might type the name of people who are friends in each row filling in the Vertex 1 and Vertex 2 columns"
  45. 45. "Click on the Show Graph button (directly above the graph pane) to show the network of friendships"
  46. 46. "To calculate graph metrics first click on the Graph Metric button on the Analysis section of the NodeXL Ribbon."
  47. 47. "Vertex metrics can be mapped onto visual attributes. The graph legend shows that Degree is mapped to Size and Betweenness Centrality is mapped to Opacity."
  48. 48. You can now handle your social capital The social capital is the "resources embedded in one's social networks, resources that can be accessed or mobilized through ties in the networks" [Lin 2008]
  49. 49. name Guillaume Erétéo account mail mentorOf mentorOf organization organization manages contributes contributes answers