Week 11 - Communities in Networks

Dad Joke

The guy who stole my diary died yesterday.

My thoughts are with his family.

Housekeeping

• Make an appointment for Self Assessment Reflection review
• Submit Exam Questions ASAP
• What to do on Thursday - R Lab or activity?
• No class on Tuesday, November 5th
  • Conversation on Discord instead
  • Post 1 question and 1 thing you’ve learned
  • Respond to 2 other posts

Plan for today

• Groups in networks review
• Discussion questions
• R

Community Detection Review

• What is a component? (Hint: there’s often one “giant” component)
• What is a clique?
• What is the weakness of cliques as a way of identifying groups?
• What is a k-plex? (Hint: related to cliques)
• The goal of most community detection algorithms is high modularity. What does that mean?

Core and Periphery Review

• Why do groups often have a core and a periphery?
• Given some of the other theories we’ve talked about, how would you expect the periphery to differ from the core?
• What role does the periphery have in protests (Barberá et al. reading)?
• What is one way to identify who is in the core or periphery?

Coreness Example

Discussion Questions

• Do k-plexes really happen? Are you really connected to everyone but one person?
• Clustering coefficient
• Homophily vs. cliques
• Networks vs. communities
• Minimum size of core