THE LUDIC FALLACY
If a coin flips head 10 times in a row, what's the probability it flips head also on the 11th throw?
The correct answer is *more* than 50%.
(thread, 1/N)
If a coin flips head 10 times in a row, what's the probability it flips head also on the 11th throw?
The correct answer is *more* than 50%.
(thread, 1/N)
2/ A statistics textbook would say: throws are independent, so the probabilities are always 50%.
In the real world, however there are more possibilities. Perhaps, the coin is loaded or the person throwing the coin does so in a way which results in a higher chance of heads.
In the real world, however there are more possibilities. Perhaps, the coin is loaded or the person throwing the coin does so in a way which results in a higher chance of heads.
3/ (The thought experiment above is taken from Nassim Nicholas Taleb's Incerto).
In the real world, the right answer would be: 50% + 50% times the probability that the throw is not a "textbook throw". The result is strictly >50%.
What does this have to do with the pandemic?
In the real world, the right answer would be: 50% + 50% times the probability that the throw is not a "textbook throw". The result is strictly >50%.
What does this have to do with the pandemic?
5/ I see an extreme focus on the official data provided by the authorities and a great deal of negligence in checking its accuracy (apart, perhaps, in the case of China's data).
Most analyses are made as if they were a textbook exercise, where data is assumed to be correct.
Most analyses are made as if they were a textbook exercise, where data is assumed to be correct.
6/ To be clear: I suspect no foul play from any government. I'm not saying anyone is manipulating data.
I'm saying that data might be incorrect because:
- limited testing capabilities
- people are afraid to go to hospitals
- waiting queues
- false positives / negatives
- etc.
I'm saying that data might be incorrect because:
- limited testing capabilities
- people are afraid to go to hospitals
- waiting queues
- false positives / negatives
- etc.
7/ For example, following Bergamo's mayor's claims that "for each COVID death there are 3 who die at home of pneumonia without a test", and prompted by @balajis, I investigated the total number of deaths regardless of cause in towns of Bergamo province, and found shocking results
8/ Here is the thread showing cues that official Italian data is undercounting cases and deaths.
This shouldn't be surprising because some ITALIAN DOCTORS HAVE BEEN SAYING SO FOR DAYS.
And yet this seems neglected by most.
This shouldn't be surprising because some ITALIAN DOCTORS HAVE BEEN SAYING SO FOR DAYS.
And yet this seems neglected by most.
9/ Let's not fall prey of the ludic fallacy and assume that this is a game whose odds and data we know perfectly.
We don't, and our analyses and strategies should address this.
Below, a call for crowdsourced data to get more reliable information.
We don't, and our analyses and strategies should address this.
Below, a call for crowdsourced data to get more reliable information.
10/ The above is incredibly important, because:
- if the Italian lockdown is working less well than expected
- if more people are dying than official numbers shown
This is information which governments must know before they base their new policies on wrong or incomplete data.
- if the Italian lockdown is working less well than expected
- if more people are dying than official numbers shown
This is information which governments must know before they base their new policies on wrong or incomplete data.
11/ TL;DR:
- The pandemic is not a textbook exercise where data can be assumed to be correct and exhaustive
- We must attempt to estimate the amount of undertesting
and of shadow mortality (or assume it's high)
- Please provide me with the data for your city as per tweet #9 🙏
- The pandemic is not a textbook exercise where data can be assumed to be correct and exhaustive
- We must attempt to estimate the amount of undertesting
and of shadow mortality (or assume it's high)
- Please provide me with the data for your city as per tweet #9 🙏
