Surely if you’re ready for more than 10% of 1-in-10 events, your probabilities are just as wrong as other people’s; it’s just that your risk management is better.
That is why I don’t like probabilities for what are fundamentally one-off events.
I think it's clear that there are some events that may be rare but which are cheaper to plan ahead for than to deal with after the fact, and vice versa (e.g. for many people self insuring against minor losses like appliance failures makes sense).
A: 10% chance you lose 100$. Preparing costs 5$
B: 10% chance you lose 100$. Preparing costs 15$
C: 10% chance you lose 200$. Preparing costs 15$
D: 10% chance you lose 200$. Preparing costs 30$
E: 10% chance you win 100$. Ticket costs 20$
F: 10% chance you win 100$. Ticket costs 5$
You prepare for A & C. You buy tickets for F
Think of it like choosing when to fold in poker
G: 5% chance one of your parents die, preparation costs $X
H: 3% chance you die, preparation costs $Y.
What at what values of $X and $Y do you prepare?
The 5%/X 3%/Y question is also hard to answer since one also has to consider how much is it mitigating, if I survive with chronic pain or something then that loses value. Assuming full mitigation:
I'd be willing to pay ~16000$ to skip a 1/30 chance of death (valuing ~480000$ to live ~50 years, or 9600/year being-alive tax)
For my parents I'd be willing to pay ~9000$ to skip a 1/20 chance of one of their's death. (valuing ~180000$ for them to live ~30 years, or 6000/year being-alive tax)
My suggestion is you don't have enough information to claim I'm making any specific mistake.
This sounds like a distinction without meaning. Using "people mistake my preparation for me believing that it will happen, so they are dumb" is weird. You're acting as if you think it will happen, of course people think you think it will happen. Why else would you bother preparing? You're not buying 10% of the sandbags you'd need, you're buying 100% of them because nothing else would do.
"Oh but I'm smarter" but your belief is leading you to take the same actions as the person who thinks 10% == yes, so in what way is it smarter? In what way is it different?
"Prepare for" is not the same thing as "think it will certainly happen". It's a case of making your cost-benefit calculations appropriately. You don't do all the things that you'd do if you thought it was 100% going to happen, you do a cheap subset.
I didn't think I'd need it - I thought it'd end up like SARS or h1n1. But it cost me $30 or something and I can afford to lose that so why not.
I bought some Bitcoin fairly early. I thought it was stupid but there was a small chance I was wrong.
In both these cases if I'd been sure I'd have acted very differently!
I'm unsure about a lot of things so sometimes I try to get on both sides of a subject.
As Alexander said repeatedly, it's cost-benefit analysis. See my other post in this thread.
If you go through life only preparing for the things you are certain will happen, you are quite likely to experience some avoidable unpleasantness.
Chanting "cost benefit analysis" doesn't change anything.
That isn't the case. Preparation isn't a binary state either - people can be more or less prepared for an occurrence. The estimated likelihood of an event changes how much time and effort should be spent preparing to it.
There is a big difference in how people behave if they thing there is a 0%, 0.05% or 98% chance of being mugged when they go outside for example. The 0.05% case would rationally start avoiding people late at night or not carrying valuables. The 98% person would not go outside.
Of course, if you persist in dismissing everything that makes a difference, then you will never figure out what the difference is.
You are being inconsistent in the way you presume (mostly mistakenly, I believe) various opinions and motives on the part of Scott Alexander, while attempting to reject opinions, motives and rational thought as being relevant to the behavior of people who prepared for C19.
> Chanting "cost benefit analysis" doesn't change anything.
Well, I agree that "chanting" (i.e. explaining to someone who will not listen, apparently) will not change anything (and least of all your understanding of the issues), but actually practicing cost-benefit analysis effectively does make a difference - as we can see, for example, in the difference in how C19 is progressing in South Korea and in Britain.
> "Oh but I'm smarter" but your belief...
Case in point.
The article says Nate Silver had Trump's chances at a little worse than 1 in 3. The average person is going to sit through 17 presidential elections.
I don't have to be very clever to say that Trump winning is totally consistent with the model; and anyone who was caught by surprise has failed to understand probability. 29% is not saying no chance of victory and it isn't really that surprising. It isn't even a forecast of defeat if you think about it. It is evidence that a defeat was likely, but a modeled probability is not a forecast - it is evidence used in forecasting.
I'm really claiming that most people will hear "10% chance of disaster!" then after it didn't pan out 9 times they'll start talking about the boy who cried wolf or stopped clocks when the disaster strikes the 10th time. I have a massive advantage over them, because that is exactly the wrong attitude towards probabilities.
Not necessarily; as Alexander mentioned repeatedly, it depends on the cost of repeatedly preparing unnecessarily versus the cost of not being prepared that one time it happens.
Just about the whole of aviation safety, to give one extended example, is based on this principle.
Disagree, it depends how much it costs to be ready, and how much it costs to be unprepared if the 1-in-10 event happens.