
Why Nate Silver, Sam Wang and Everyone Else Were Wrong - digital55
https://www.quantamagazine.org/20161108-why-nate-silver-and-sam-wang-are-wrong/#more-32023
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ffjffsfr
Everyone claiming that polls or forecasters were wrong should really do their
homework and think what 'forecasting' is all about. It is not about predicting
future with 100% certainty. It is about calculating odds of outcomes. You can
calculate odds of Trump winning and put them at 40%, you can put them at 1% or
90%. In neither of cases you are wrong or right when he wins. Odds of winning
are not 'verified' in any way. If you say that there is 50% chance of coin
flipping on tails you are not wrong when it flips on head.

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gph
Perhaps, but I still think the fact that so many polls had Clinton's chances
of winning well above 90% is indicative of some incorrect assumptions within
their models. Especially considering how they were off in nearly every single
swing state. Most forecasters had Clinton winning Wisc/Michigan at over 90%,
and considerable advantages in most the other battleground states.

It would be like if I gave you a quarter and said it has a 75% chance of it
coming up heads (ignore physics), then you flip it five times and it comes up
tails each time. Sure it could be a run of coincidence, but I'd also put
serious consideration into my statistical model.

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basch
the polls were not expecting a globalist establishment incumbent vs a
nationalist populist outsider. the polls treated him like GOP candidate, when
he was more of a parasite to the party, using its skin to get on every ballet
as a "top two" candidate.

at least Nate Silver's part two to this piece will include "i was less
confident than most others" [https://fivethirtyeight.com/features/how-i-acted-
like-a-pund...](https://fivethirtyeight.com/features/how-i-acted-like-a-
pundit-and-screwed-up-on-donald-trump/)

Silver really took Trump's ascension to the GOP throne as a lesson.
[http://www.politico.com/story/2016/11/nate-silver-
huffington...](http://www.politico.com/story/2016/11/nate-silver-huffington-
post-polls-twitter-230815)

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totalZero
Didn't Nate Silver acknowledge that this was a tough election for his methods
because of the highly unusual nature of Trump's campaign, among other things?

EDIT: found some indication of this from May of this year:
[http://fivethirtyeight.com/features/how-i-acted-like-a-
pundi...](http://fivethirtyeight.com/features/how-i-acted-like-a-pundit-and-
screwed-up-on-donald-trump/)

~~~
simonbarker87
I've been listening to the 538 daily podcast for the last couple of weeks (as
a Brit it's been a great way to get an insight on how the US system works
rather than just the politics on the surface) and, when on the show, Nate
would not be drawn on saying who he thought was going to win. He really seemed
to be going out of his way to say that the model is based on polls and those
polls can be off, the model is only as good as the information that's put into
it.

The model had a pretty low Hilary chance a few days ago and then it ticked up
at the end to over 70% for her but Jody Avirgan and Harry Enten were warning
about pollsters' tendency to herd (I think that's what they called it) at the
end and so the final polls can be less reliable due to this.

I'm looking forward to their wash up podcast and then I'm checking out of
politics, between Brexit and this it's been a bumpy year.

~~~
zzalpha
Also notable that they mentioned repeatedly that:

1\. Polls in key swing states like Michigan have been consistently bad over
the years, and there hasn't been a lot of high quality polling in those states
during the election, which meant there was a lot of uncertainty in those
states.

2\. State polls tend to be correlated. That means if the polling is off in
Michigan, it'd probably be off in Pennsylvania and Wisconsin as well, and in
the same direction. And, what a shock, all of them were tipping point states,
and all of them had polling errors that swung in Trump's favour.

3\. Trump was well within the polling error of winning by election time. That
is, while FiveThirtyEight had Hillary with 2-1 odds, that was with significant
errors bars due to uncertainty, and it runs both ways.

To be honest, listening to their podcast and reading their posts, I was
preparing myself for a potential Trump win.

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bhauer
Actually, the LA Times made a fairly big deal about forecasting correctly.

[https://twitter.com/latimes/status/796360500091252736](https://twitter.com/latimes/status/796360500091252736)

~~~
maxerickson
They predicted Clinton would win the electoral college.

