Will Mail-in-ballots Swing the Election?


The 2020 election has unprecedented levels of absentee and early voting, fueled by worries about the current COVID-19 pandemic. For states like Virginia, who are offering early voting for the first time, the ability to efficiently receive and count all the votes is uncertain. Mail in ballots have faced scrutiny as funding for USPS has been cut, reducing the speed with which votes are delivered, and leading some to demand drop off ballot boxes. This is especially worrying in states where mail-in ballots must be received, not postmarked, by election day.

Some states begin counting early votes on November 3rd, while others start weeks before. John Mendelsohn coined the term “red mirage” to describe a possible outcome where in-person tallies on election day depict a victory for Trump that changes drastically as mail-in votes are counted. With President Trump challenging the legitimacy of mail-in ballots, some fear that the President will bank on the election day results and refuse to acknowledge the legitimacy of votes tabulated after November 3rd.


For all states that reported mail in ballot data by party, the number of votes for each candidate on election day was predicted. The assumption was made that no mail in votes would be counted by election day in order to determine the significance of mail in ballots. Key observations, including states that are flipped as a result of mail-in ballots, can be found in the final column.


$$BIDEN election day = BIDEN oracle - Request mail ballots*ballots requested by Democrats $$

$$ TRUMP election day = TRUMP oracle - Request mail ballots*ballots requested by Republicans $$

$$ Percent BIDEN election day = (BIDEN election day)/(BIDEN election day + TRUMP election day) $$

$$ Percent TRUMP election day = (TRUMP election day)/(BIDEN election day + TRUMP election day) $$


Mail in ballots will have a clear impact in the 2020 election. In North Carolina 68% of registered voters are choosing to vote by mail. This group is predominantly Democrats, transforming predictions for the state from a clear Trump win at 66% of the vote to a tossup. Pennsylvania, with its key electoral college votes, is predicted to switch for Trump to Biden. Florida, the home of the incumbent president, is also expected to revert from Trump to Biden. Additional flipped states can be found in the key observations table above.

Several assumptions were made in predicting the vote counts for election day. First of all, it was assumed that no mail-in ballots would be counted. In states such as Florida, that have been using mail in ballots for over 20 years, this is not realistic. However, in states such as Pennsylvania that do not begin counting ballots until the evening of the election, this assumption is much more reasonable. Secondly, the model does not take into account the actions of Independent voters. In Iowa, which is integral to the outcome of the election, independent voters make up 38% of the population. Thirdly, it was assumed that voters will vote for the presidential candidate of the party they are registered for. Lastly, predictions were only made for states that report mail in ballot data by party.

Notably, the majority of citizens voting by mail are Democrats. Out of the states that report mail in ballot requests by party, only Idaho has more requests from Republican voters. Therefore, the “red mirage” of Trump to Biden wins predicted by John Mendelsohn may in fact occur.

SOURCES https://www.nytimes.com/interactive/2020/us/elections/absentee-ballot-early-voting.html https://www.washingtonpost.com/graphics/2020/elections/early-voting-numbers-so-far/