Why election models didn't predict Trump's victory — A primer on how polls and election models work

phl43

well, there were "mainstream" polls (used as a propaganda in the proclintonian media), sampled a bit over 1000, sometimes less, often massively oversampling registered Dem. voters... what do you expect?

and there was the biggest poll of 50000 (1000 per state) showing completely different picture (and of course used as a prooaganda in the anticlintonian, usually non-mainstream media)

google "election poll 50000"

A cursory glance through Fivethirtyeight's collected poll data shows a survey with over 84,000 voters (CCES/YouGov) giving Clinton a +4 percentage point lead, with 538 adjusting that to +2. Google and SurveyMonkey routinely had surveys of 20,000+ individuals, with one SurveyMonkey one having 70,000 with Clinton +5 (+4 adjusted). There was no clear reason to prefer your poll (whichever that one was) over these. https://projects.fivethirtyeight.com/2016-election-forecast/national-polls/

And it should go without saying that Clinton did end up at +2 nationally.

4phl439y

I'm sure pollsters sometimes "cheat" by constructing biased samples, but this can happen even if you're honest because, as I explain in my post, polling is really difficult to do. To my mind, the problem had more to do with commentators who were making mistaken inferences based on the polls, than with the polls themselves, although evidently some of them got things badly wrong.