538 model & poll tracker thread

[Annatar]

Looking at how Nate has described the 538 model vs the Economist model it seems the main difference is the 538 model is basically completely driven by state polling with national polls only being used to apply a trend adjustment whereas the Economist model is built to a larger extent around national polls.

Because of this it is quite possible Trump's chances of winning won't drop that much in the 538 model even as we get closer to election day as it is based off state polls and if polls like Marquette which had Trump up 4% in WI and Muhlenberg which had Trump up 4% in PA keep coming out, even on election day Trump will have a reasonable chance of winning due to the possibility of a polling error.

The 538 and Economist model also use different polls, for example Morris has stated their model does not use Emerson at all because they don't like the polls' methodology whereas 538 does use Emerson so the 2 models differ on what polls they use as well.   

[Annatar]

https://twitter.com/gelliottmorris/status/1298797791523868673?s=20

The model isn't based off national polls, Nate Silver has pointed this out, the model works off state polling, the national polls are only used to apply a trend adjustment so it doesn't matter what the national poll say, the 538 model just operates based off state polls.

For example on September 7 2016, Clinton was projected to win PA by 4% and had a 72% chance of doing so, today Biden is projected to win PA by 4% and has a 71% chance of doing so, if you go state by state, the margins and probability from 2016 are the same in 2020, the only difference is compared to this time in 2016 Trump is doing much worse nationally but not worse in a lot of states.

[Annatar]

So they just added a bunch of those USC polls. Biden's polling lead jumped back over 9 points and Trump's at his lowest support in over a month. Yet the model didn't move in this mornings update. I really don't understand how it works anymore.

Update: The new "social desirability bias" Trafalgar poll of Michigan affected the model more than weeks worth of national polls showing Biden up in the double digits.

The model doesn't work off national polls, it is a state based model.

[Annatar]

So they just added a bunch of those USC polls. Biden's polling lead jumped back over 9 points and Trump's at his lowest support in over a month. Yet the model didn't move in this mornings update. I really don't understand how it works anymore.

Update: The new "social desirability bias" Trafalgar poll of Michigan affected the model more than weeks worth of national polls showing Biden up in the double digits.

The model doesn't work off national polls, it is a state based model.

That's not entirely true. There have been days where Biden's % has dropped because his national numbers have dropped.

Well the national polls are used for trend adjustment it's true, but the effect is really minor, almost non-existent, for all intents and purposes the model basically runs on state polls.