Reciprocity
Measure mutual connections in directed networks
Reciprocity quantifies the probability that if A→B exists, then B→A also exists.
What It Computes
Reciprocity = (# bidirectional edges) / (# total edges)
Range: 0 to 1
When to Use It
- Social networks: Mutual friendships vs one-way follows
- Communication: Bidirectional vs broadcast
- Collaboration: Mutual vs unidirectional relationships
Example
Interpretation:
- ~0.0: One-way relationships (broadcast)
- ~0.5: Mix of mutual and one-way
- ~1.0: Mostly mutual (friendships)
Use Cases
Social Network Type
- Twitter: Low reciprocity (~0.2) - follows
- Facebook: High reciprocity (~0.8) - friendships
Community Health
Higher reciprocity = more engaged community