Wednesday, November 9, 2016

Quick stats refresher: analyzing the 2016 election

This is an economics and physics blog, but I'll do one post about some of the post-mortem analysis happening out there because it touches on math.

I've seen some arguments out there that such and such loss of voters by one candidate in one election and a shift in another election being interpreted as voters moving from one candidate to another. This is only true under the condition that either turnout is 100% (and therefore moves are zero sum) or voters are drawn from the same pool, like this:


However, the more likely scenario is that voters are drawn from differing pools (e.g. polarized political affiliation):


In this case, "shifts" of votes from one side to the other could just be pulling more or fewer voters from your pool. This is behind partisan response bias.

A specific example I have in mind is that Obama won among white voters in the Midwest in 2008 (or some similar situation), but Trump won them in 2016, therefore a racism wasn't a factor. However it could be the two pools above represent racist and non-racist voters and Obama pulled more from the non-racist reserve in 2008 while Trump pulled more racist voters from the racist pool in 2016. (I'm not ruling out a candidate pulling from both pools, just simplified to that here).

The thing is that some analysis out there appears to assume turnout was 100% (in which case, voter shifts are zero sum) or from the same pool. This isn't necessarily true.

1 comment:

  1. �� I like how you're so blunt about it. I would never go there because I've foolishly wasted time following the battle between so-called "social justice warriors" (SJWs) and what I call anti-(SJW)-warriors (ASJWW?). Then I suppose there are the social-injustice-warriors (SIW?) (basically Nazis I guess), who get offended if you DON'T call them racists �� ...��...��. (I don't interact w those but I've observed a few of their Twitter convos). In any case it's like walking on egg shells if you let it get to you.

    Your post doesn't offend me in the least but the ASJWWs would probably be "triggered." Many people have their triggers it seems, not excluding myself I suppose.

    I'm starting to deeply hate the whole subject, but there's no getting away from it it seems. ��

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