"Next Tuesday all of you will go to the polls, will stand there in the polling place and make a decision. I think when you make that decision, it might be well if you would ask yourself, are you better off than you were four years ago? Is it easier for you to go and buy things in the stores than it was four years ago? Is there more or less unemployment in the country than there was four years ago?"

-- Ronald Reagan, October 28, 1980

That was perhaps the most brilliant campaign line in modern history. Asking if you are better off than you were four years ago perfectly captures why Americans vote for change.

Yet Reagan was very wrong about one thing. "Next Tuesday all of you will go to the polls," he said. But not every eligible voter actually votes. One group in particular tends to have a low voter turnout: the poor and the unemployed. In other words, those most likely to be worse off than they were four years ago.

As persuasive as it sounds, it's hard to find a correlation between the state of the economy on election day and the odds of an incumbent being reelected. Statistician Nate Silver looked at the data going back to President Taft in 1912 and found that both the unemployment rate on election day and the change in unemployment during an incumbent's term doesn't tell you much about his chances of being reelected. Same if you narrow it down to just the post-World War II period. Even if you are "more or less deliberately cherry-picking" the data, Silver wrote, the correlation between unemployment and presidential elections is elusive.

Why that is may have been explained 30 years ago by Yale political scientist Steven Rosenstone:

When a person suffers economic adversity his scarce resources are spent holding body and soul together, not on remote concerns like politics. Economic problems both increase the opportunity costs of political participation and reduce a person's capacity to attend to politics.

There's a simple way of showing this. After every election, the Census Bureau publishes a detailed report on the demographics of voters -- not just the country at large, but those who actually stepped into a voting booth. In the last five elections (and likely more if we had older data), unemployed people have been significantly less likely to vote than those with a job:

Election

Percent of Unemployed Who Voted

Percent of Employed Who Voted

2008

54.7%

65.9%

2004

51.4%

65.9%

2000

39.8%

60.5%

1996

37.2%

55.2%

1992

46.2%

63.8%

Source: Census Bureau.

This extends to incomes. In the 2008 election, 79.8% of those with incomes above $100,000 voted, compared with 59% of those with incomes below $50,000, and 51.9% of those with incomes below $20,000. In the 2004 election, 81.3% of those with incomes above $100,000 voted, versus 48.3% of those with incomes below $20,000.

Voter turnout, therefore, doesn't tend to be a pure representation of our economy. It skews toward those who are doing all right, and thus are more likely to actually be better off than they were four years ago even if the whole economy isn't.

In the spirit of election day, let's take a poll. Are you better off than you were four years ago? Cast your vote, and share your thoughts in the comment section below.

Fool contributor Morgan Housel doesn't own shares in any of the companies mentioned in this article. Follow him on Twitter @TMFHousel. The Motley Fool has a disclosure policy. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. Try any of our Foolish newsletter services free for 30 days.