What is power?

• Long, varied history in the social sciences
  • One version is the capacity to achieve one’s will
  • How do we do that? Through capital
• Social networks are one way of measuring “social capital”
• Who has power in a social network?

Degree Centrality

• Counts the number of edges each node has
• In, out, or all

## [1] "Degree Centrality:"

## 1 2 3 4 5 6 7 8 
## 4 3 1 2 2 4 2 2

Closeness Centrality

Average distance to all other nodes

Betweenness Centrality

Counts the number of shortest paths that go through each node. This is based on the value of being in a “structural hole”

Eigenvector Centrality

Who is connected to the most important people? If you have only one friend, but that friend is the President, then you are still powerful.

Network-level

Density

Directed \[ \frac{\sum(edges)}{N * (N-1)} \]

Undirected: Multiply by 2

Centralization

How unequal is the centrality between nodes?

Using metadata to find Paul Revere

• Where did the data come from?
  • What kind of network was it?
• Did this make you think differently about metadata?
  • About privacy?

Homework

• Reading
• Keep working on R