medical advances
Conflating Convenience with Correctness
My email and facebook feed is filled with pictures and videos of exponential growth functions.
 
The flood originates, I believe, in epidemiological hubris, namely that:
 
1. The form of equation governing infection growth is known and unchanging; and,
 
2. That the parameters of the equation — the now infamous R0 — also don’t change, and therefore can be reliably estimated from the data.
 
Yes, you can “fit” the initial *recorded* covid infections to an exponential curve — as you could “eyeballs” in the early phases of the 1999 internet bubble. But as Herbert Stein famously observed “if something cannot go on forever it will stop”; very likely, I might add tailing off before it stops for many phenomena. The reasons will of course vary from case to case.
 
The conflation of the convenience of a mathematical model with is correctness is common in economics (eg Cobb-douglas production functions) and financial risk models (normally distributed price changes). Sometimes, as in 2008, with disastrous consequences.

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