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Nassim Talebs case against Nate Silver is bad math

m.nautil.us

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Re: Nassim Talebs case against Nate Silver is bad math

#31

Post by backpropaganda »

vertis wrote: post #19
KorematsuFred wrote: post #8

I have zero respect for election forecasters because I think they are not any better than astrologers. Nate silver has used the word probability in a way that is not consistent with mathematical definition of probability so often in this context. Taleb despite being brilliant mathematician is actually pretty mediocre when it comes to real world. A lot of his "discoveries" such as "skin in the game" are well known to…

I've found twitter not to be a good forum for this kind of thing. Leaving the current pair alone, I've had a few times where more public figures can't determine easily that you're not one of the trolls, that and the fact that they almost certainly don't follow you and have an understanding of your context and goodwill. For the most part, I've stopped following anyone that doesn't follow me in return on twitter. Takin…

Is there any reason to believe that some other medium won't have this exact problem? For instance, if you were to meet a public figure at a public event, do you think they will behave any differently? To me it seems like this is more a problem of public figures having a high number of people who want to talk to them or troll them, than of Twitter as a medium.

Re: Nassim Talebs case against Nate Silver is bad math

#33

Post by hwestiii »

Nassem Taleb is an arrogant asshole who can't write. I tried reading "The Black Swan" and gave up in a flurry of swearing after less than 100 pages because he utterly failed to justify any of his breathless assertions with anything resembling an argument. Assertion after assertion with no reasoning linking them. Game to Silver on points. At least he can back up his arguments with explanations.

Re: Nassim Talebs case against Nate Silver is bad math

#34

Post by LanguageGamer »

From a business perspective, the volatility of Silver's models seem like a feature - they enhance the drama / sensationalism of election coverage. One week, he's telling me candidate X will likely win, the next week it's candidate Y, and I'm on the edge of my seat.

If Silver really believed these probabilities were correct, he should be willing make bets with these odds, otherwise his incentives are distorted.

Re: Nassim Talebs case against Nate Silver is bad math

#35

Post by ska »

baddox wrote: post #27
brian_cloutier wrote: post #16

Earlier quoted context omitted.

Do you have an example of a time where Nate Silver has shown a misunderstanding of probability? Everything I've read by him has seemed informed.

The best criticism I can come up with is that 538 probably doesn't do a sufficient job of explaining to its audience that their published probabilities are predictions for what would happen if the event occurred today . This seems to be one of Taleb's (and others') criticisms of their predictions: that they don't consider the probability of major unexpected events occurring between now and the event (like an athlete…

I think overall 538 did a pretty good job of communicating a difficult subject to a lay audience, but agree this point could perhaps be communicated better.

I don't know of a good way to try and capture these sort of events meaningfully, do you?

Re: Nassim Talebs case against Nate Silver is bad math

#36

Post by iainmerrick »

jerf wrote: post #4

"Since Silver’s forecasts begin with probability models, it’s safe to assume they obey all the rules, including Bayes’, and would be arbitrage-free." I'll do the author the courtesy of assuming they've got a more expanded version of their argument in their head and just failed to express that, but I don't think that follows at all. I don't think there's a constraint on "Nate Silver has a probability model" that mathe…

I thought that bit was very well-expressed. Let’s see if I can explain what I think I understood by it...

If you’re buying and selling bets on a range of events, you can only be immune from arbitrage if all your bets are mutually consistent. For example, if you’re offering 3:1 odds on event X, you can’t offer more than 1:3 on the complementary event ~X (where exactly one of X and ~X must happen). That’s pretty obvious, but there a lot of much trickier variations.

“Nate Silver has a probability model” just means his forecasts are derived from a self-consistent model about the probabilities of all the micro-events that make up the election. That fits with the information FiveThirtyEight have published about their methods, so it seems correct to me.

One way Silver’s model could be invalid is if there’s just a bug, and a single event is tracked in multiple inconsistent ways. For example, if the model unknowingly projected odds for the same politician in both the presidential election and a senate seat, without accounting for the fact that you can’t win both at once. But if that’s the criticism Taleb is making, he should be able to put his finger on a specific bug, which he doesn’t seem to have done.

Another way Silver could be wrong is if his models are far too volatile, so you know if the probabilities shoot up or down a long way they’ll almost certainly revert to the mean again. I imagine you could run arbitrage against that.

It’s far from clear that that’s the case, though. It could be that his models are volatile but still pretty close to reality, in which case just betting against every big swing in Silver’s model would be like trying to make money by predicting day-today movement on the stock market.

Re: Nassim Talebs case against Nate Silver is bad math

#37

Post by eridius »

baddox wrote: post #27
brian_cloutier wrote: post #16

Earlier quoted context omitted.

Do you have an example of a time where Nate Silver has shown a misunderstanding of probability? Everything I've read by him has seemed informed.

The best criticism I can come up with is that 538 probably doesn't do a sufficient job of explaining to its audience that their published probabilities are predictions for what would happen if the event occurred today . This seems to be one of Taleb's (and others') criticisms of their predictions: that they don't consider the probability of major unexpected events occurring between now and the event (like an athlete…

That seems like a pretty big difference to gloss over. Why are they publishing probabilities for if the event were to happen today? The event isn't happening today!

Re: Nassim Talebs case against Nate Silver is bad math

#38

Post by throw2016 »

KorematsuFred wrote: post #8

I have zero respect for election forecasters because I think they are not any better than astrologers. Nate silver has used the word probability in a way that is not consistent with mathematical definition of probability so often in this context. Taleb despite being brilliant mathematician is actually pretty mediocre when it comes to real world. A lot of his "discoveries" such as "skin in the game" are well known to…

Piketty's extensive data on global wages raises serious questions about Pinker's narrative. And if there is still doubt Pinker's data sources [1] and interpretation are questionable to say the least.

Here is Pinker himself admitting his selective use of data [2] Watch his answer at 4.30. This is extremely poor use of stats, and makes him look a side character apologist in Hunger Games.

And here is an even more substantial criticism of Pinker's approach by Leon Wieseltier in the newrepublic [3].

[1] https://www.jasonhickel.org/blog/2019/2/3/pinker-and-global-...

[2] https://www.youtube.com/watch?v=xAQ0BfcftBA

[3] https://newrepublic.com/article/114548/leon-wieseltier-respo...

Re: Nassim Talebs case against Nate Silver is bad math

#39

Post by tshaddox »

andrewla wrote: post #14

As I understand it, the feud in its current form started from a tweet from Dinesh D'Souza [1] in which he interpreted Nate Silver's statement that "Dems, GOP winning House are 'both extremely possible'" to mean that they had gone from an 80% chance of winning to a 50% chance. Taleb inexplicably chose this as the hill to die on [2] and wrote a lengthy and technical paper to refute, and replied (on the [2] thread) "Whe…

Yeah, "extremely possible" is perhaps a poor choice of words, and could be interpreted uncharitably as a hedge against any outcome, but I think there's an obvious charitable interpretation too: that things that have a 20% chance of occurring turn out to occur around 20% of the time. No one would be blown away by surprise if I proclaimed "SIX!" then rolled a six-sided die and got a six, but that's even less likely than 20%.

So it's reasonable to say that, if 538 claims that an event has a 20% probability of happening, and that event happens, no one should be astonished. Of course, such events ought to happen about 20% of the time, if 538's models are good. And that evaluation is precisely what 538 published a few days ago: https://projects.fivethirtyeight.com/checking-our-work/

Re: Nassim Talebs case against Nate Silver is bad math

#40

Post by pohl »

eridius wrote: post #37
baddox wrote: post #27

Earlier quoted context omitted.

The best criticism I can come up with is that 538 probably doesn't do a sufficient job of explaining to its audience that their published probabilities are predictions for what would happen if the event occurred today . This seems to be one of Taleb's (and others') criticisms of their predictions: that they don't consider the probability of major unexpected events occurring between now and the event (like an athlete…

That seems like a pretty big difference to gloss over. Why are they publishing probabilities for if the event were to happen today? The event isn't happening today!

I know, right? Every time my meteorologist gives me a probability of rain on a day that it doesn't rain I ask the same question.
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