The bias might narrow slightly as more votes are counted; late-counted votes tend to be Democratic in most states. - Nate Silver, 538, "Senate Polls Had A Significant Democratic Skew"

  1. Does the data bear that assertion? (this is coming from Nate Silver. Of course it does :)

  2. If so, what are the proposed plausible explanations? I'd prefer explanations that are backed up with data, or at least are testable/falsifiable.

  • 6
    Just a guess as to one theory: late votes tend to come from highly urbanized areas (due to the volume of voting that needs counting). Large urban areas tend to lean Democrat.
    – user1530
    Nov 5, 2014 at 17:24
  • @DA. - I used to vote in NYC - that's as urbanized as you can get :)Didn't see a single long line in several years. Possible but unlikely.
    – user4012
    Nov 5, 2014 at 17:26
  • My understanding of late counts is that it's not the in-person counts that are the hang-up (as most of those are tabulated electronically) but all the provisional ballots that may be cast that need hand-counting.
    – user1530
    Nov 5, 2014 at 17:28
  • 1
    @DA agreed. It isn't how long it takes people to vote in person that holds things up but the sheer amount of people voting leads to higher provisional ballots and other irregularities that take longer to sort out properly. Given that these areas already trend Democratic, that's what leads to the blue shift late in counting. Nov 5, 2014 at 17:37
  • 1
    I tend to think the late vote is due to the Democrat base covers a lot of voters who usually are not actively involved or particularly interested in the election, and who vote only under the last-minute pushes from the party and its volunteers.
    – r13
    Jul 18, 2021 at 23:46

3 Answers 3


In Australia, small, rural ballot stations tend to have their counting finished before large, urban ballot stations within the same electorate, because there's fewer votes to count. The former tend to be more right wing, the latter more left wing.

  • 2
    But shouldn't larger districts also have more people doing the counting? So some source with explanation would be nice for that
    – user45891
    Nov 6, 2014 at 13:24
  • The AEC needs to supply enough people at small booths to conduct a booth including toilet, meals, supervision, chief electoral officer in booth. Large booths distribute such "overhead" costs more effectively, so have fewer AEC officers per booth. Nov 7, 2014 at 3:24
  • Same thing in the US. Jul 18, 2021 at 23:11

Many states report absentee and postal votes at a different time to election day votes. Typically votes on Election day are recorded and counted electronically. Postal votes are counted by hand after the Election Day votes have been counted.

Most years this allows for a rapid calling of the winner, as the number of postal votes is small in comparison to Election day votes. This was not the case in 2020.

Moreover postal votes trended blue, again 538 noted:

Democrats are much likelier than Republicans to say they will vote by mail — which makes sense given that Democrats also tend to be more supportive of mail voting. (By contrast, the Republican standard bearer, President Trump, has repeatedly and inaccurately assailed mail voting as ripe for fraud.)

So in states that counted postal votes later, a "blue shift" was seen. In States that counted postal votes first there would be a "Red shift". For example in Ohio, the early votes were counted, then Election day votes and finally late arriving postal votes. So first Biden would have an advantage, then Trump would come back, and lastly Biden would gain again.

The shifts were forecast in each state, and you can compare this to the actual results to test or falsify this model.

  • And California reports last. Jul 19, 2021 at 10:44

It has to do with Trump's attacks on mail-in ballots. What the other person said about urban vs rural is a factor, but recently, it has to do with Democrats preferring mail in ballots, especially in states where mail in voting is new.

  • 8
    I would suggest this question from 2014 about a quote from 2014 about the 2014 Midterms cannot be answered with Trump's attacks on mail in ballots in 2020. If anything, it's the other way around: Trump attacked mail in ballots in 2020 already before the election, because it was already known that they would lean Democrat. Similarly he claimed victory based on early votes because it was known in 2020 (as evidenced by this question from 2014) that later votes tend to favor Democrats.
    – Peter
    Jul 19, 2021 at 11:44

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