The math behind absentee ballots rarely changing election results

There’s a reason why people say absentee ballots rarely change election results from what is reported on the machines on election night – simple math.

Let’s say there is an election with 2,000 votes on election day and 100 people who voted by absentee ballot. Candidate “A” won on Election Day by 1,010 votes. Candidate “B” won 990 votes.

The television news reported that the election results are too close to call – with only a ten vote margin giving Candidate “A” an election night win.
While technically the results are too close to call, statistically Candidate “B” has an very up hill battle to win. Let’s look at the math.

The 10 vote margin means that Candidate B got 49.5% of the vote on election night. Candidate B needs to get 50% of all absentees plus and additional ten votes (50+10=60) or a total of 60% of all absentee votes. In other words, Candidate B must perform 10.5% better with absentee voters then Election Day.

Can that happen? Sure, but generally the voting patterns about a candidate on Election Day are similar to Absentee Voters. And while it’s possible that absentees voters went more strongly for Candidate B then Candidate A, the margins are rarely the necessary difference to overcome under performance on Election Day.

Absentee ballots generally are counted but its very rare that they overturn Election Day machine counts. Candidates hoping to overturn Election Day results are best to hope for glitches in election night reporting or machine errors, not what absentee voters put on their ballot.