Degree Centrality
Count direct connections - simplest centrality metric
Degree centrality measures how many connections a node has. For directed graphs, distinguishes in-degree (incoming) and out-degree (outgoing).
What It Computes
For each node:
- In-degree: Number of incoming edges
- Out-degree: Number of outgoing edges
- Total degree: In + out (or just degree for undirected)
When to Use It
- Quick analysis: Fastest centrality metric
- Volume metrics: Total activity level
- Hubs: Nodes with many connections
Performance
Time: O(V)
Space: O(V)
Scales to: Unlimited (trivial operation)
Example
Use Cases
Transaction Volume
Financial: Accounts with highest transaction counts
Social Popularity
Social: Users with most followers (in-degree)
Activity Monitoring
Systems: Services with most connections
Degree vs PageRank
- Degree: Quantity of connections
- PageRank: Quality of connections
Example:
- Node A: 1000 connections from low-value nodes
- Node B: 10 connections from high-value nodes
Degree → A wins
PageRank → B likely wins
When to Use Each
Use Degree when:
- Simple volume matters
- Quick exploration needed
- Baseline metric before sophisticated analysis
Use PageRank when:
- Quality matters
- Influence propagation
- Ranking by importance
See Also
- PageRank - Quality-weighted importance
- Betweenness - Bridge position