The Basics of Social Network

AnalysisAdriana Berlanga & Rory Sie

LN SNA Seminar series, November 15th 2011

Outline

•History

•Examples

•Network Data

•Analysis

History

Social Network Analysis

Psychology Anthropology

1930s: Jacob Moreno

sociogram

htt

p:/

/in

stit

uto

mom

en

to.w

ord

pre

ss.c

om

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”

htt

p:/

/ww

w.r

cgd

.isr

.um

ich

.ed

uh

ttp

://w

ww

.ur.

um

ich

.ed

u

1920s: Warner and Mayo

Mayo

Warner

Hawthorne

htt

p:/

/ad

min

istr

aci

on

1en

linea.b

log

spot.

com

htt

p:/

/ww

w.w

olfra

malp

ha.c

om

focus on relationships

effect

1920s: Warner and Mayo

Mayo

Warner

htt

p:/

/ad

min

istr

aci

on

1en

linea.b

log

spot.

com

htt

p:/

/ww

w.w

olfra

malp

ha.c

om

adapted from Scott, 2000

cliquesevery person is separated by only one step

Social Networks•1950s:

‘network’ (Barnes, Bott, Nadel)

•1960s: Density and reachability (Mitchell)

A

BC

D

E

A-B-C-E

Mark Granovetter

•Getting a Job (1974)

•Strength of weak ties (1983)

://w

ww

.sta

nfo

rd.e

du

/dep

t/so

c/p

eop

le/m

gra

novett

er/

History

Social Network Analysis

Psychology AnthropologyHawthorne

NetworksGraph theory

Sociogram

Graph theory Strength of weak ties

Examples

‘broker’ (Burt, 2004)

centrality = power(Krackhardt, 1990)

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

Data collection

Ego network

ego network

alter

alter

but.... self-perceived

ask for connectionsask connections if they are connected

Snowball method

but.... self-perceived

ask for connectionsask connections for their connectionsuntil you reach a stopping criterion

Complete networks

monitor email traffic

or monitor tweets

Data storage

Adjacency matrix (R, UCINET)

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)

Data storage

Pajek network (Pajek, UCINET)

Analysis: network

•Density

•Connectivity k

•Centralization

A

DCB

E

Analysis: community

Clique

A

D

CB

EF

every person in a clique can be reached within 1 step

Analysis: community

N-clique

A

D

CB

EF

every person can be reached within n steps. ABCF is a 2-clique

Analysis: community

A

D

CB

EF

Faction

http://www.physorg.com/news/2011-01-mathematical-groups-factions.html

Analysis: individual

A

DC

B

EF

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

Summary

• Why?

• encourages re-use

• reduce burden on teacher

• discover effective and efficient (sub)communities

• Data collection

• Which technique?

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

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