Count all 13 directed triad types · Compare to random null model
Network Parameters
Triad Census (Z-score vs ER null)
Theory
Network motifs (Milo et al. 2002) are subgraph patterns that occur significantly more than in random networks. The directed triad census enumerates all 13 non-isomorphic 3-node directed subgraph types (MAN codes: 003, 012, 102, ..., 300).
The Z-score: (count − μ_rand)/σ_rand measures statistical enrichment. Biological networks over-express feed-forward loops (021D); social networks over-express mutual triads (300).