Network Analysis by Barry Wellman

Three Ways to Look at Reality Categories Categories All Possess One or More Properties as an Aggregate of Individuals All Possess One or More Properties as an Aggregate of Individuals Examples: Men, Developed Countries Examples: Men, Developed Countries Groups Groups (Almost) All Densely-Knit Within Tight Boundary (Almost) All Densely-Knit Within Tight Boundary Thought of as a Solitary Unit (Really a Special Network) Thought of as a Solitary Unit (Really a Special Network) Family, Workgroup, Community Family, Workgroup, Community Networks Networks Set of Connected Units: People, Organizations, Networks Set of Connected Units: People, Organizations, Networks Can Belong to Multiple Networks Can Belong to Multiple Networks Examples: Friendship, Organizational, Inter-, World-System, Internet Examples: Friendship, Organizational, Inter-, World-System, Internet

Nodes, Relationships & Ties Nodes: A Unit That Possibly is Connected Nodes: A Unit That Possibly is Connected Individuals, Households, Groups, Organizations, States Individuals, Households, Groups, Organizations, States Relationships (A Specific Type of Connection) Relationships (A Specific Type of Connection) Gives Emotional Support Gives Emotional Support Sends Money To Sends Money To Attacks Attacks Ties (One or More Relationships) Ties (One or More Relationships) Friendship (with possibly many relationships) Friendship (with possibly many relationships)

A Network is More Than The Sum of Its Ties A Network Consists of One or More Nodes A Network Consists of One or More Nodes Could be Persons, Organizations, Groups, Nations Could be Persons, Organizations, Groups, Nations Connected by One or More Ties Connected by One or More Ties Could be One or More Relationships Could be One or More Relationships That Form Distinct, Analyzable Patterns That Form Distinct, Analyzable Patterns Can Study Patterns of Relationships OR Ties Can Study Patterns of Relationships OR Ties 5

Overview - Journals Wellman founded, Connections, 1977 Wellman founded, Connections, 1977 Informal journal: “Useful” articles, news, gossip, grants, abstracts, book summaries Informal journal: “Useful” articles, news, gossip, grants, abstracts, book summaries Bill Richards, Tom Valente edit now Bill Richards, Tom Valente edit now Lin Freeman founded, Social Networks, 1978 Lin Freeman founded, Social Networks, 1978 Formal journal: Refereed articles Formal journal: Refereed articles Ronald Breiger now co-editor Ronald Breiger now co-editor David Krackhardt founded, J of Social Structure, 2000 David Krackhardt founded, J of Social Structure, 2000 Online, Refereed Online, Refereed Lots of visuals Lots of visuals Articles Appear Occasionally when their time has come Articles Appear Occasionally when their time has come 6

Overview – Key Books 1) Elizabeth Bott, Family & Social Network, ) J. Clyde Mitchell, Networks, Norms & Institutions, ) Holland & Leinhardt, Perspectives on Social Network Research,1979 4) S. D. Berkowitz, An Introduction to Structural Analysis, ) Knoke & Kuklinski, Network Analysis, ) Charles Tilly, Big Structures, Large Processes, Huge Comparisons, ) David Knoke, Political Networks, ) John Scott, Social Network Analysis, ) Ron Burt, Structural Holes, ) Manuel Castells, The Rise of Network Society, 1996, ) Wasserman & Faust, Social Network Analysis, ) Nan Lin, Social Capital (monograph & reader), ) Monge & Contractor, Theories of Communication Networks, 2003

Overview – Software 1)UCINet – Whole Network Analysis 2)MultiNet – Whole Network Analysis 3)P*Star – Dyadic Analysis 4)Krackplot – Network Visualization 5)Pajek – Network Visualization 6)Personal Network Analysis 1)SPSS/SAS – See Wellman, et al. “How To…” papers

The Social Network Approach The world is composed of networks - not densely-knit, tightly-bounded groups The world is composed of networks - not densely-knit, tightly-bounded groups Networks provide flexible means of social organization and of thinking about social organization Networks provide flexible means of social organization and of thinking about social organization Networks have emergent properties of structure and composition Networks have emergent properties of structure and composition Networks are a major source of social capital mobilizable in themselves and from their contents Networks are a major source of social capital mobilizable in themselves and from their contents Networks are self-shaping and reflexive Networks are self-shaping and reflexive Networks scale up to networks of networks Networks scale up to networks of networks 9

Networked Individualism Moving from a society bound up in little boxes to a multiple network – and networking – society Moving from a society bound up in little boxes to a multiple network – and networking – society Networks are a flexible means of social organization Networks are a flexible means of social organization Networks are a major source of social capital: mobilizable in themselves & from their contents Networks are a major source of social capital: mobilizable in themselves & from their contents Networks link: Networks link: Persons Persons Within organizations Within organizations Between organizations and institutions Between organizations and institutions 10

Barry Wellman co-editor Social Structure: A Network Approach JAI-Elsevier Press 1998 Little BoxesGlocalization Networked Individualism

Ways of Looking at Networks Whole Networks & Personal Networks Whole Networks & Personal Networks Focus on the System or on the Set of Individuals Focus on the System or on the Set of Individuals Graphs & Matrices Graphs & Matrices We dream in graphs We dream in graphs We analyze in matrices We analyze in matrices 12

Whole Social Networks Comprehensive Set of Role Relationships in a Full System Comprehensive Set of Role Relationships in a Full System Analyze Each Role Relationship – Can Combine Analyze Each Role Relationship – Can Combine Composition: % Women; Heterogeneity; % Weak Ties Composition: % Women; Heterogeneity; % Weak Ties Structure: Pattern of Ties Structure: Pattern of Ties Village, Organization, Kinship, Enclaves, World-System Village, Organization, Kinship, Enclaves, World-System Typical Methods: Cliques, Blocks, Centrality, Flows Typical Methods: Cliques, Blocks, Centrality, Flows (1) What is the Real Structure of an Organization? (1) What is the Real Structure of an Organization? (2) How Does Information Flow Through a Village? (2) How Does Information Flow Through a Village? 13

Duality of Persons & Groups People Link Groups People Link Groups Groups Link People Groups Link People An Interpersonal Net is an Interorganizational Net An Interpersonal Net is an Interorganizational Net Ronald Breiger 1973 Ronald Breiger

15 The Dualities of Persons and Groups -- Graphs

16 Dualities of Persons and Groups -- Matrices

17 Dualities of Persons and Groups: Event-Event Matrix

Neat Whole Network Methods QAP QAP Regression of Matrices Regression of Matrices Example: Co-Citation (Intellectual Tie) Example: Co-Citation (Intellectual Tie) Predicts Better than Friendship (Social Tie) To Inter-Citation Clustering: High Density; Tight Boundaries (“Groups”) Clustering: High Density; Tight Boundaries (“Groups”) Block Modeling Block Modeling Similar Role Relationships, Not Necessarily Clusters Similar Role Relationships, Not Necessarily Clusters Canada & Mexico in Same Block – US Dominated Canada & Mexico in Same Block – US Dominated 18

19 Erickson, 1988: From a Matrix >...

20... To a Block Model

Costs of Whole Network Analysis Requires a Roster of Entire Population Requires a Roster of Entire Population Requires (Imposition of) a Social Boundary Requires (Imposition of) a Social Boundary This May Assume What You Want to Find This May Assume What You Want to Find Hard to Handle Missing Data Hard to Handle Missing Data Needs Special Analytic Packages Needs Special Analytic Packages Becoming Easier to Use Becoming Easier to Use 21

Personal Social Networks Ptolemaic Ego-Centered View Ptolemaic Ego-Centered View Good for Unbounded Networks Good for Unbounded Networks Often Uses Survey Research Often Uses Survey Research Example: Example: (1) Do Densely-Knit Networks Provide More Support? (structure) (1) Do Densely-Knit Networks Provide More Support? (structure) (2) Do More Central People Get More Support?(network) (2) Do More Central People Get More Support?(network) (2) Do Women Provide More Support? (composition) (2) Do Women Provide More Support? (composition) (3) Do Face-to-Face Ties Provide More Support Than Internet Ties? (relational) (3) Do Face-to-Face Ties Provide More Support Than Internet Ties? (relational) (4) Are People More Isolated Now? (ego) (4) Are People More Isolated Now? (ego) 22