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Reverse-engineering the problematic tail behavior of Fivethirtyeight forecast

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Re: Reverse-engineering the problematic tail behavior of Fivethirtyeight forecast

#61

Post by jimmygrapes »

ceilingcorner wrote: post #42
gamblor956 wrote: post #38

Earlier quoted context omitted.

They were generally correct with their prediction except in 3 states where nobody had been doing detailed polling because the pollsters didn't think it would matter. It simply wouldn't have been possible for the models to be more accurate with the data they had. As they say, bad data in, bad data out. That's why this time around the pollsters made sure to be more thorough in their polling.

> That's why this time around the pollsters made sure to be more thorough in their polling. "This time is different." I've heard that enough times to be highly skeptical. I'm also deeply skeptical of the notion that polling is even remotely correlated to actual results. Cultural and historical trends play a drastically higher role and are almost always left out.

The shy Tory factor[0] is likely to be even stronger this year than in 2016 when it comes to polls. After 4+ years of being harangued and called every name in the book by the vast majority of national culture (movies, music, TV, news, social media, news-entertainment), along with increasingly hostile projects such as https://donaldtrump.watch/ I imagine less of his more subdued supporters are going to be honest with pollsters.

[0]: https://en.wikipedia.org/wiki/Shy_Tory_factor

Re: Reverse-engineering the problematic tail behavior of Fivethirtyeight forecast

#63

Post by klyrs »

The negative correlation between NJ and AK is curious. What I'd like to see here (and in all of these forecast sites) is some confidence analysis. If you pick Trump in NJ, looking at the plots, you've selected a tiny fraction of the data to examine. Who cares if the predicted value is wonky; show me the confidence interval!

Treating this as a tea-leaf reading (that is, deliberately searching for meaning via free association, without investing it with a truth value) I'm reminded of the "own the libs" meme. I see folks on foxnews.com comments bragging about it; I see lefties complaining about it, but I suspect that it's overblown and not actually a driver behind people's decision-making. But that's what comes up for me when I see "NJ goes Trump" forcing "AK goes Biden".

I'm amused by the resulting thought experiment... if dems started airing "socialists for Trump" campaigns in otherwise safe GOP states, would it move the needle there? Even sillier: if you aired those ads in NJ, would it move the needle in AK?

Re: Reverse-engineering the problematic tail behavior of Fivethirtyeight forecast

#64

Post by Ibethewalrus »

hn_throwaway_99 wrote: post #24
mathattack wrote: post #21

The first problem with the model is it grossly missed the last election. I still think it’s good reading.

Are you referring to the 2016 election? If so, you are wrong. 538 gave Trump a higher chance of winning than pretty much every independent pollster.

nope, you're wrong.

538 gave Hillary a 71.4% chance of winning

https://projects.fivethirtyeight.com/2016-election-forecast/

Re: Reverse-engineering the problematic tail behavior of Fivethirtyeight forecast

#65

Post by [deleted] »

preommr wrote: post #8

> It didn't take very long to do the analysis. But it did then take another hour or so to write it up. It's very interesting to see how long it takes people to do things. I am amazed that entire article took 1 hour to type up. I've spent entire afternoons trying to write shallower pieces of work.

[deleted]

Re: Reverse-engineering the problematic tail behavior of Fivethirtyeight forecast

#66

Post by tracer4201 »

ceilingcorner wrote: post #36
abnry wrote: post #35

Earlier quoted context omitted.

They said Trump had a 1 in 4 chance. That's very high. NYT had something like 1 in 20 chance for Trump.

That doesn't really answer my question. It only indicates that they were slightly less wrong than every other media source, not that they have a good model. If I had a laptop that only worked 1/4th of the time, rather than 1/20th of the time, would that make it a reliable laptop? I don't think so.

It seems like you are conflating probabilities with absolute certainties. If I had a 1:10 probability of winning the lottery, I would probably take it. If I had a 1:20 probability of getting injured if I leave my house today, I’d stay home. If I did get out but didn’t get injured doesn’t mean the model was wrong.

Re: Reverse-engineering the problematic tail behavior of Fivethirtyeight forecast

#67

Post by ceilingcorner »

jimmygrapes wrote: post #61
ceilingcorner wrote: post #42

Earlier quoted context omitted.

> That's why this time around the pollsters made sure to be more thorough in their polling. "This time is different." I've heard that enough times to be highly skeptical. I'm also deeply skeptical of the notion that polling is even remotely correlated to actual results. Cultural and historical trends play a drastically higher role and are almost always left out.

The shy Tory factor[0] is likely to be even stronger this year than in 2016 when it comes to polls. After 4+ years of being harangued and called every name in the book by the vast majority of national culture (movies, music, TV, news, social media, news-entertainment), along with increasingly hostile projects such as https://donaldtrump.watch/ I imagine less of his more subdued supporters are going to be honest with…

Yep. I see this everywhere, both online and in person.

Re: Reverse-engineering the problematic tail behavior of Fivethirtyeight forecast

#68

Post by [deleted] »

hn_throwaway_99 wrote: post #24
mathattack wrote: post #21

The first problem with the model is it grossly missed the last election. I still think it’s good reading.

Are you referring to the 2016 election? If so, you are wrong. 538 gave Trump a higher chance of winning than pretty much every independent pollster.

[deleted]

Re: Reverse-engineering the problematic tail behavior of Fivethirtyeight forecast

#69

Post by sampo »

Funny thing, can't submit this to r/politics, as they seem to have a tightly curated whitelist of allowed domains that must "Be notable, as defined by our domain notability guidelines. Notable domains will consist of news organizations, research organizations, political advocacy groups, governmental agencies / bodies, and political parties."

And apparently columbia.edu does not fulfill those criteria.

Re: Reverse-engineering the problematic tail behavior of Fivethirtyeight forecast

#70

Post by thetinguy »

sampo wrote: post #69

Funny thing, can't submit this to r/politics, as they seem to have a tightly curated whitelist of allowed domains that must "Be notable, as defined by our domain notability guidelines. Notable domains will consist of news organizations, research organizations, political advocacy groups, governmental agencies / bodies, and political parties." And apparently columbia.edu does not fulfill those criteria.

Did you try asking the moderators to add it to the whitelist?
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