Social Network Theory Dr. Zaheeruddin Asif
What is a Network? Nodes Relationships Properties Directional Symmetric Flow Mulitplexity
Nodes
Relationships Directional Friendship Advice seeking Buyer/supplier
Relationships Symmetric Strategic alliance Club membership Co-authorship
Transitivity
Reciprocity
Network Scope Ego-centric Socio-centric Open-system
Socio-centric
Combined ego-networks of five active authors
Centrality Degree centrality: "An important node is involved in large number of interactions“
Centrality Closeness centrality: "An important node is typically “close” to, and can communicate quickly with, the other nodes in the network. “
Centrality Betweenness centrality: "An important node will lie on a high proportion of paths between other nodes in the network."
Hubs and Bridges (in-degree) Betweenness = Size
Closeness Centrality
Betweenness Centrality
Theories of Networks Social Capital Structural Holes Social Exchange Collective Action Cognitive theories Homophily theories
Social Capital Pierre Bourdieu
Social Capital Pierre Bourdieu "the sum of the resources, actual or virtual, that accrue to an individual or a group by virtue of possessing a durable network of more or less institutionalized relationships of mutual acquaintance and recognition"
Social exchange Social exchange or dependence theories hold that people form ties with whom they can exchange resources, and only those ties that are mutually beneficial will be sustained over time.
Propinquity Geographically close nodes are more likely to be connected.
Homophily Pairs can be said to be homophilous if they their characteristics match in a proportion greater than expected in the population from which they are drawn or the network of which they are a part (Verbrugge 1977).
Homophily Homophily theories claim that people form ties with those they consider similar to themselves.
References http://www.commetrix.de/IRIS http://www.oecd.org/dataoecd/7/23/41858618.pdf http://www.vincos.it/wp-content/uploads/2009/06/wmsn_animated_1024.gif