ALL MODELS ARE WRONG. SOME MODELS ARE USEFUL. But to be really useful, models must be based on accurate data, and a clear understanding of the processes being modeled, two things nobody has for the Wuhan coronavirus outbreak. ARE COVID-19 MODELS A SOUND BASIS FOR PUBLIC POLICY?.

That said, all policymaking, even in unforeseen emergencies, is based on some sort of model, even if it’s just decision makers’ rough impressions of what’s likely to happen. And I’ll be very happy if things are no worse than the IHME model predicts.

And why has no one modeled the effect of quarantining New York? Good question.