Number 07/Networks & contagion/Epidemiology
The Clustering Ratio
The quantity
The ratio of local clustering coefficient to mean degree in a contact network. Above a threshold, outbreaks are smaller than the same reproduction number would predict in a well-mixed population.
01Why it matters
It explains why identical R produces different outbreak sizes in different settings, and why interventions that change mixing can matter more than those that change transmission.
02Expected value
Outbreak size should fall sharply above a clustering ratio of roughly one.
03How it would be measured
Contact tracing data or digital contact networks give both quantities directly.
04What would refute it
If outbreak size depends only on R, the ratio is irrelevant.