Thread by @NeilShenvi

People who are sharing Dr. Erickson's video about #COVID19, please read:

Starting at 4:30, he notes that 19% of #COVID19 tests in CA are positive and then "extrapolates" to 5M COVID cases in CA and then uses this number to argue against a lockdown. This is horrifically wrong. 1/

A parallel argument would be "50% of cancer biopsies in CA are positive; therefore, 50% of people in CA have cancer." That's nonsense.

It doesn't follow that everything Dr. Erickson is false. It doesn't follow that lockdowns are still needed. But two things do follow. 2/

First, the fact that Dr. Erickson could make such a basic, basic mistake removes any warrant for us thinking he speaks from a position of authority on this issue. In the same way, if I say "I am a PhD chemist. I also believe in the four elements of fire, air, wind, and water" 3/

then you have no reason to think I am a trustworthy authority or am speaking from a position of expertise, regardless of my credentials.

Second, if you shared this video without noticing this major error, I'd gently suggest that you're not in a good epistemic position 4/

I'm not saying everything you believe is wrong. But if this slipped by you, it means you probably should be listening more carefully and more broadly.

There are many other mistakes in the video which have been discussed elsewhere, but I'll close by noting that two of the 5/

largest emergency medicine organizations in the U.S. repudiated it this morning.

Please think critically and carefully about these issues, especially before you share and spread information through social media. 6/6

acep.org/corona/COVID-1…