Surprise at the polls - what went wrong?

They were way off, predicting Obama would win New Hampshire by double-digit margins. So what happened? And how could they be so wrong? And what does this all mean for future polls?

For the Obama campaign, this was not supposed to happen. Polls heading into the primary had the Illinois senator leading by 10 to 14 points and seeming to surge. But on Wednesday, pollsters were in soul-searching mode, trying to figure out what went wrong with their reads on voter intent, especially figuring out how many new voters would come ouT.

"It looks like what happened was the doubling of new voters in Iowa compared to the 33 percent increase in New Hampshire makes one understate Obama in Iowa and overstate Obama in New Hampshire," said Richard Day, ABC7 pollster.

Day, who has conducted polls for ABC7 for years, says that was complicated by nearly one-fifth of New Hampshire voters waiting until primary day to decide, making tracking back to Hillary Clinton nearly impossible.

"The best predictor is who voted before, and then who's new," said Day. "It makes it a nightmare for a pollster."

U.S. Senator Dick Durbin discounted the poll phenomena in the 1980s and 1990s, where the undecideds break toward the white and biracial candidates.

"That could be an element here, but I don't want to say that was determinative at all. I just think there were other factors at work here," Durbin said.

But it happened to Harold Washington in 1983 when his winning margin for Chicago mayor was two points, versus the 14-point lead he had going into voting day. In Douglas Wilder's 1989 race for Virginia governor, he squeaked out a win despite leading pre-election surveys by a wide margin. And Indian-American Bobby Jindal triumphed in the 2007 Louisiana gubernatorial race after losing in 2003, when he had a big lead just before Election Day.

So for president in 2008 on the Democratic side, Day says in the future it would seem that Clinton has the advantage because Obama's strength is based upon his ability to attract brand new voters.