Thread by @MWalschaers

I'm making a presentation to explain quantum physics to high school students and it's time for a little break. So let's take a quick moment to ponder about #confinementSaison2 and in particular these graphs... 1/n

The more I look at these two graphs, the more they depress me. Why? Because we learn that France has had a nice and steady exponential growth every since July. In particular in France, the curve is remarkably clean given that they are real-world data. 2/n

What makes it clean? Well the fact that we have 4 months of data and three orders of magnitude of cases. Without data for several orders of magnitude of cases, calling something exponential doesn't make much sense. However, here the data are remarkably stable over time. 3/n

Why is this depressing? Because it actually suggest that all the measures we have implemented over the last four months have had close to no impact. The exception seems to be the middle of September, but when we look at testing, we see that there were just fewer test... 4/n

Isn't it all just an artefact of testing? No, this figure clearly shows that the density of cases is really increasing in society. 5/n

So why is this happening? There seem to be three schools of thought:
1) We haven't been strict enough and should not have relaxed restrictions in summer.
2) The rules are good, but people simply don't follow them.
3) We have been focusing on the wrong things.
6/n

Personally, I doubt there is a simple explanation, but it seems frustratingly clear that there is a lot of uncertainty. There are many cognitive biases that mislead our intuitions about the pandemic (e.g. we probably overestimate the amount of people who break the rules). 7/n

I am quite sure that the confinement will work if it is rigorously implemented (infectious deceases do not spread when there is no one to infect), but it has an enormous cost. But what is the optimal trajectory, one that reduces the exponential slope further? 8/n

Let me finish with a positive note: the slope of the curve is much smaller than in spring. We have done good things, the question is what those things were and what should we do more to further reduce the slope in the next deconfinement period. 9/9

Given that this thread got more attention than I expected, I will refer those who are interested to a nice little thread by @SylviaFysica on biases

https://twitter.com/SylviaFysica/status/1318896351862755328?s=19