I don’t know that it was always this way, but, for as long as I can remember, just as we move into the final weeks of the Presidential campaign the focus shifts to the undecided voters. “Who are they?” the news anchors ask. “And how might they determine the outcome of this election?”

. . . To put them in perspective, I think of being on an airplane. The flight attendant comes down the aisle with her food cart and, eventually, parks it beside my seat. “Can I interest you in the chicken?” she asks. “Or would you prefer the platter of shit with bits of broken glass in it?”

To be undecided in this election is to pause for a moment and then ask how the chicken is cooked.

I mean, really, what’s to be confused about?

. . . As Election Day nears, polling organizations like to narrow their samples to people who say they are registered voters. They often narrow them further to those they consider likely voters. That's because in a country where barely more than half of eligible voters usually show up for presidential elections, pollsters want their polls to reflect the views of those likeliest to vote.

Q: Is that hard to do?

A: Quite hard, since no one will truly know who will vote on Election Day until that day is over. In fact, virtually every polling organization has its own way of determining who likely voters are.

Q: Why is this such a problem?

A: Because nobody is 100 percent sure how to do this properly. And the challenge is being compounded this year because many think Obama's candidacy could spark higher turnout than usual from certain voters, including young voters and minorities. The question pollsters face is whether, and how, to adjust their tests for likely voters to reflect this.

In identifying likely voters, the AP does not build in an assumption of higher turnout by blacks or young voters. Pew Director Andrew Kohut says that reflecting exceptionally heavy African-American turnout in the Democratic primaries, Pew's model of likely voters now shows blacks as 12 percent of voters, compared to 9 percent in 2004