[Traster]

> I’d think that if Trump were to win New Jersey or, even more so, California, that this would most likely happen only as part of a national landslide of the sort envisioned by Scott Adams or whatever.

That's a valid intuition to have but you can also clearly make the argument that if Trump wins California you're in such a weird scenario that using the traditional wisdom about correlation is dangerous. The point that 538 have tried repeatedly to make is that firstly: if you're conservative in your level of confidence you'll give a higher likelihood to outliers, and secondly: It's not particularly useful to focus on whether X has a 3% or 4% chance.

If Trump wins California, we aren't going to be talking about whether the chance was 3% or 0.3% we're going to be talking about that Nuclear explosion that wiped out 25million Californians.

For the same logic the reason that Trump winning Alaska given winning New Jersey is lower than given losing New Jersy is because your sample size is rubbish. The chance of Trump winning Alaska given losing New Jersey is an accurate number, the number of Trump winning Alaska given winning New Jersey is like saying "How likely is it Trump wins Alaska given the UK gains US statehood" it's like.... well... if that happens then we're so far outside of what the model thinks can happen then you should be that we're just gonna say it's 50:50 - because who the hell knows.

It's not like saying "Oh well if X swing state goes blue, Y will probably follow", the scenarios in this article are so bizarre that the model should rightly be very cautious and probably default to either refusing to give an answer or just default to 50:50 or the same probably ignoring that data. The implicit bias in this analysis seems to be that if NJ went Red that would be because Trump won by a big margin, but that's not a likely enough scenario to actually get numbers for, and is so unlikely that things like "The supreme court threw out all the ballots for inner city areas" start to become valid possibilities.

[noirbot]

It is worth noting that they explicitly aren't accounting for any election tampering/throwing out ballots in the model, so that final hypothetical isn't something they're factoring in. Your "an explosion kills everyone in LA" is closer to the sort of things that the model is "considering" in so much as a pile of statistical code has any understanding of what could happen in the real world to cause the outcome it's putting forward.

[evgen]

This is the important point here IMHO. There are two errors that the tails need to deal with, voter shifts that are missed by polling and black swan events that completely upend the table. I think that the 528 model lumps a lot of the long tail into the second category, which then basically becomes a "let's throw out most of the rules and make wild guesses" territory. There is so little worthwhile information in those tails I am really surprised that this is the focus of the disagreement.