Does One Vote Make a Difference?

It's Election Day!

Every time an election rolls around, we're treated to lots of public service announcements and various other admonishments to "get out there and do your civic duty! Every vote counts!"

But, does it?

Economists Casey B. Mulligan and Charles G. Hunter took a look at that very question, and they came up with some surprises.

Mulligan and Hunter found in a 2001 study that only one of every 100,000 votes cast in federal elections, and one of every 15,000 votes cast in state legislative elections, “mattered in the sense that they were cast for a candidate that officially tied or won by one vote.”

Their study of 16,577 national elections from 1898 through 1992 found that only one had been decided by a single vote. It was the 1910 election in New York’s 36th Congressional District, won by a Democrat who claimed 20,685 votes to the Republican candidate’s 20,684.

Of those elections, the median margin of victory was 22 percentage points and 18,021 actual votes.

Okay, that's looking at 94 years of national elections. What about on the statewide level?

Mulligan and Hunter also analyzed 40,036 state legislative elections from 1968 through 1989 and found only seven that had been decided by a single vote. Of those elections, the median margin of victory was 25 percentage points and 3,257 actual votes.

In other words, the chance that your vote will be the decisive or pivotal one in a national election is almost zilch. The same goes for state legislative elections.

Admittedly, the odds are small (1 in 10 million at best, 1 in 100 million at worst), but better than some things:

Still, the odds of your one vote deciding a presidential election are still better than your odds of matching all six numbers of Powerball, which are smaller than 1 in 175 million.

That does not mean that it never happens:

• a 1982 state House election in Maine in which the victor won 1,387 votes to the loser’s 1,386 votes

• a 1982 state Senate race in Massachusetts in which the victor won 5,352 votes to the loser’s 5,351; a subsequent recount late found wider margin

• a 1980 state House race in Utah in which the victor won 1,931 votes to the loser’s 1,930 votes

• a 1978 state Senate race in North Dakota in which the victor won 2,459 votes to the loser’s 2,458 votes; a subsequent recount found the margin to be six votes

• a 1970 state House race in Rhode Island in which the victor won 1,760 votes to the loser’s 1,759

• a 1970 state House race in Missouri in which the victor won 4,819 votes to the loser’s 4,818 votes

• and a 1968 state House race in Wisconsin in which the victor won 6,522 votes to the loser’s 6,521 votes; a subsequent recount found the margin to be two votes, not one.

More on their research can be found here.

Now get out and vote.