Networks

in what follows, see The Macroscope
original illustrations by Scott Weingart

Basics

These are nodes. Nodes can be anything.

These are edges. Any relationship can be an edge.

Can your data be represented as a graph?

Nodes and Edges can have attributes

Kinds of edges

a dyad

a dyad where the relationship is reciprocated

Transivity is the concept that when A is connected to B and C, B and C will also be connected.
What does that imply in, for instance, correspondence networks?

Kinds of networks

unweighted

weighted

directed

citation graph as directed network

bipartite or 2-mode network

Exercise

Build a social network of students in this class
Who are the nodes?
What are the links?

nb many network metrics assume 1-mode graph. That's not to say they can't be calculated on a 2-mode graph; it's just they might not mean what you think they mean.

Metrics

Path Length

My Bacon Number is 3

Degree Centrality

Closeness Centrality

Betweeness Centrality

The difference a metric makes

Here we go to Clement Levallois' tutorial on why networks p35

same network, different centralities!

and directionality matters!

more