538 Model Megathread

[bilaps]

They weighted Monmouth poll pretty modestly cause of a samling size i guess. So Trump is still at 55% in FL in polls only.

[bilaps]

I'm not sure what polls are responsible, but 538's model has Trump still surging.

In this case it's ipsos national poll and also these FL polls not weighted too much to move the needle there for Clinton.

[bilaps]

After he put in those Google polls, especially the DC one, I lost all faith in this model.

You are wrong. He wrote an article regarding that and he weights those tracking state polls from google and ipsos not too much.

[bilaps]

I'm not sure what polls are responsible, but 538's model has Trump still surging.

In this case it's ipsos national poll and also these FL polls not weighted too much to move the needle there for Clinton.

The Ipsos looks like the main culprit. However, it was conducted mostly in the midst of Deplorables/Pneumoniagate, so perhaps the improvement since then will show up more in the coming days.

Nope, it's 15-19 september. So starts thursday. It's during birther issue if anything

[bilaps]

After he put in those Google polls, especially the DC one, I lost all faith in this model.

You are wrong. He wrote an article regarding that and he weights those tracking state polls from google and ipsos not too much.

Yep, but there are so much more of these trash polls being churned out that, even if he weighs them less, they eventually overwhelm the good pollsters, like Monmouth.

I don't think that is the case. Would you give me an example? And Monmouth poll from FL was weighted less because of sample size.

[bilaps]

I'm not sure what polls are responsible, but 538's model has Trump still surging.

That's what I'm scratching my head over. I get that he includes all the funky tracking polls, but you'd think more traditional polls would get weighted higher

Even the tracking polls don't show Trump expanding his lead anymore, though. I wish there was a place on the site where you could see a list of the most recent additions to the model forecast.

It's right here: http://projects.fivethirtyeight.com/2016-election-forecast/updates/

Thank you. Wish I had seen this earlier.

It might be new; I just saw it the other day for the first time.

Don't know when it was introduced but it's there for at least a month.

[bilaps]

I don't know how 538 adjustes polls? Anyone with an insight. Didn't read topic from the start, maybe I should try that before asking but if someone wants to help right away...

[bilaps]

To me the thing that makes the least amount of sense is there have been 3 Florida polls released since yesterday with Clinton up (+1,+5,+5), yet Trump's odds in Florida keep spiking?

Well, it has sense in this way. One of those polls which is weighted highest is adjusted to Trump +1, one was adjusted to Clinton +1 or +2 i forgot and Monmouth was adjusted slightly to Clinton +4 but is weighted less cause of samle size. So, when you look top 6 weighted polls, you have Trump up in 3, one tie and Clinton up in 2.

Again I don't know why he adjusted for example Siena poll from Clinton up 1 to Trump up 1 but with those adjustments and weighing it's clear why Trump has better chances.

[bilaps]

IIRC the NYC model doesn't factor in national polls and they aren't using these 50 state online polls.  538 model basically uses pretty much every poll there is (albeit with weighting) and those national polls are used to create momentum at the state level. So there is a level of garbage in/garbage out with 538, especially in periods where there are fewer live voter polls coming out, yet lots of data from these tracking polls and '50 state' polls.

Yes, his premise in a way is that states follow national numbers. So, nothing too surprising in fact that model gives far more meaning to ipsos national than fl monmouth 400 sample size.

[bilaps]

Also, he just gave Nate Cohn an explanation for adjusting Siena poll to Trump +1. He basicaly says that Siena was D leaning this cycle because their NY polls were strongest for Clinton out of 10 different pollsters.

Also says that trend goes into that 2 point adjustment, because his model shows Trump still gaining.