Social

1. The Basics of Social
Network Analysis
Adriana Berlanga & Rory Sie
LN SNA Seminar series, November 15th 2011

2. Outline
• History
• Examples
• Network Data
• Analysis

3. History
Social Network Analysis
Psychology Anthropology

4. 1930s: Jacob Moreno
sociogram
http://institutomomento.wordpress.com

5. 1950s: Cartwright and
Harary
Frank Harary
+
-
-
Dorwin Cartwright
A
B
C
“any balanced graph can be divided into two cohesive
sub-groups that are in conflict with each other”
http://www.rcgd.isr.umich.edu
http://www.ur.umich.edu

6. 1920s: Warner and
Mayo
Mayo
Warner
Hawthorne
http://administracion1enlinea.blogspot.com
http://www.wolframalpha.com
focus on relationships
effect

7. 1920s: Warner and
Mayo
Mayo
Warner
http://administracion1enlinea.blogspot.com
http://www.wolframalpha.com
adapted from Scott, 2000
cliques
every person is separated by only one step

8. Social Networks
• 1950s:
‘network’
(Barnes, Bott,
Nadel)
• 1960s:
Density and
reachability
(Mitchell)
A
B
C
D
E
A-B-C-E

9. Mark Granovetter
• Getting a Job (1974)
• Strength of weak ties (1983)
://www.stanford.edu/dept/soc/people/mgranovetter/

10. History
Social Network Analysis
Psychology Anthropology
Hawthorne
Networks
Graph theory
Sociogram
Graph theory Strength of weak ties

11. Examples
‘broker’
(Burt, 2004)
centrality = power
(Krackhardt, 1990)

12. Why?
• encourages re-use and prevent re-
invention
• increase knowledge sharing
• discover effective and efficient
(sub)communities
• reduce burden on experts/teachers
adapted from Liebowitz, 2005

13. Data collection

14. Ego network
ego network
alter
alter
but.... self-perceived
ask for connections
ask connections if they are connected

15. Snowball method
but.... self-perceived
ask for connections
ask connections for their connections
until you reach a stopping criterion

16. Complete networks
monitor email traffic
or monitor tweets

17. Data storage
Adjacency matrix (R, UCINET)

18. Data storage
<?xml version="1.0" encoding="UTF-8" standalone="yes"?><graph
label="PLN for ID " directed="1">
<node id="n26" label="n26"><att type="string" name="PeerName"
value="Rory Sie"/></node><node id="n27" label="n27"><att
type="string" name="PeerName" value="Adriana
Berlanga"/></node><edge id="e0" label="e0" source="n26"
target="n27"><att type="string" name="interaction"
value="colleague""/>
</edge>
</graph>
GML/ XGMML (Cytoscape, Gephi)

19. Data storage
Pajek network (Pajek, UCINET)

20. Analysis: network
• Density
• Connectivity k
• Centralization
A
D
C
B
E

21. Analysis: community
Clique
A
D
C
B
E
F
every person in a clique can be reached within 1 step

22. Analysis: community
N-clique
A
D
C
B
E
F
every person can be reached within n steps.
ABCF is a 2-clique

23. Analysis: community
A
D
C
B
E
F
Faction
http://www.physorg.com/news/2011-01-mathematical-groups-factions.html

24. Analysis: individual
A
D
C
B
E
F
G
H
Betweenness
network is dependent on C
Degree
G is very popular
12 12
14
17
17
18
19
19
Closeness
C and G can easily reach others

25. Summary
• Why?
• encourages re-use
• reduce burden on teacher
• discover effective and efficient (sub)communities
• Data collection
• Which technique?

26. References
• Brandes, U. (1994). A Faster Algorithm for Betweenness Centrality. Journal of Mathematical
Sociology, 25(2), 163-177.
• Burt, R. S. (2004). Structural Holes and Good Ideas. American Journal of Sociology, 110(2), 349-399.
doi:10.1086/421787
• Cartwright, D., & Harary, F. (1977). A Graph Theoretic Approach to the Investigation of System-
Environment Relationships. Journal of Mathematical Sociology, 5, 87-111.
• Granovetter, M. (1974). Getting A Job: A Study of Contacts and Careers. Cambridge, Massachusetts.
• Krackhardt, D. (1990). Assessing the Political Landscape : Structure, Cognition, and Power in
Organizations. Administrative Science Quarterly, 35(2), 342-369.
• Liebowitz, J. (2005). Linking social network analysis with the analytic hierarchy process for
knowledge mapping in organizations. Journal of Knowledge Management, 9(1), 76-86.
doi:10.1108/13673270510582974
• Scott, J. (2000). Social Network Analysis: a Handbook (p. 208). SAGE Publications, Inc.
• Factions video. http://www.physorg.com/news/2011-01-mathematical-groups-factions.html

27. Questions?
rory.sie@ou.nl
http://www.open.ou.nl/rse
openrory, maisonpoublon
Rory Sie
openrse
http://nl.linkedin.com/in/rorysie
thebigbangrory.blogspot.com

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