Key undecided voters: "Wal-mart moms"?

Sometimes seen as the great prize of U.S. electoral politics, this elusive citizen is more likely to be female, white, lacking a college education and earning less than $25,000, according Reuters/Ipsos polling data accumulated over the course of 2012.

The “undecideds” make up roughly 6 percent of the electorate, with a slightly higher concentration in an Upper Midwest region including Ohio and Wisconsin, swing states that could determine the outcome of a close election.

Even though such voters are expensive to win over and perhaps less likely to make it to the polls, they continue to capture the attention of campaigns and political analysts for their potential to tilt the result in a tight race.