Theory 06/Thresholds & Tipping/Epidemic transmission
Outbreaks Tip on Superspreading
The claim
Whether an outbreak becomes an epidemic is set by the fraction of transmission from superspreading events rather than by the reproduction number alone.
01Mechanism
When most transmission comes from a few events, the outbreak is a branching process with high variance; the same R can die out or explode depending on that fraction.
02Prediction
Extinction probability should track the superspreading fraction.
03Refutation
Extinction tracking R alone would remove the dispersion term.