The popular vote totals are not final. On Wednesday afternoon, the margin was 6.2% and rising. The pollsters who nailed it by reporting 6-7% included Rasmussen Reports, Pew Research, FOX News, Ipsos/McClatchy, CNN/Opinion Research, and the poll aggregator 538.
The worst performers were Gallup and Zogby with an 11% spread, followed by Battleground with a 3.5% average of its two models, and Marist, CBS News, and ABC News/Wash Post a 9% spread.
Interestingly, CNN and Fox News both outperformed the oldline networks – ABC, CBS, and NBC.
Predicted Spread Poll
2-5 Battleground (combined models)
5 Diageo/Hotline
6 Rasmussen Reports
6 Pew Research
7 FOX News
7 Ipsos/McClatchy
7 CNN/Opinion Research
8 IBD/TIPP
8 NBC News/Wall St. Jrnl
9 Marist
9 CBS News
9 ABC News/Wash Post
11 Reuters/C-SPAN/Zogby
11 Gallup
Overall, the polls did pretty well this year. If the Obama ground game weren't so incredibly good, they might have done a tad worse. But only 2 polls were too low on Obama's margin, while 7 were too high.
In aggregating them, one would have done fairly well by throwing out the most Democratic poll among every 4 polls.
One thing struck me as well, though this opinion is probably tainted by hindsight bias: since 1960, it might well be that the campaign staff that ran the better campaign won each election, though I don't remember a few of them (eg, 1984) well enough to be certain of that. Of course, a great candidate makes a campaign look good, especially in retrospect.
UPDATE: Even though Nate Silver at 538 was not in the poll list I used for the post, I reached out to give him his props for being essentially as good as others who predicted a 6-7% spread before Tuesday's election.
Several commenters point to 538's Tuesday afternoon prediction of a 6.1% spread, issued long after the polls opened and turnout info was filtering back.
Judging his prediction by the same standard as the pollsters on the list above — subtracting his pre-election McCain prediction (46.1%) from his pre-election Obama prediction (52%), his predicted pre-election spread would be 5.9%, very slightly farther from the current spread than a couple of the pollsters above.
538 Mon PM & Tues AM prediction
Yet even that is complicated because his last pre-election presidential prediction post (on Monday evening) put the predicted spread at 6.0%, which simply means that the 52 to 46.1% spread actually rounded up to 6.0%:
With fewer than six hours until voting begins in Dixville Notch, New Hampshire, the national polling picture has cleared up considerably. Barack Obama is on the verge of a victory, perhaps a decisive victory, in the race for the White House.The national polls have all consolidated into a range of roughly Obama +7. That is right about where our model sees the race as well, giving Obama a 6.8 point advantage in its composite of state and national polling. Our model notes, however, that candidates with large leads in the polls have had some tendency to underperform marginally on election day, and so projects an Obama win of 6.0 points tomorrow.
Silver's performance this year has been terrific, clearly establishing himself as the most reliable of the poll-based aggregators /predictors. He has an intuitive feel for numbers and knows when to tweak his models. In part because he appears to be the best out there, I hope that next time he releases his “final” predictions BEFORE the election.
As a commenter there put it, addressing Silver and his crew, "I hope you guys like lots of money."
Let's not forget Research 2000, which also nailed it with a final tally of 51-46. Yeah, I know it was the poll sponsored by Kos, but credit where credit is due - it's clear that it valued accuracy more than whatever propaganda purposes it's detractors accused it of.
It wasn't until Tuesday AFTERNOON, after the polls were open and there was turnout info available, that he changed his prediction to 6.1%.
Personally, I would look to pre-election predictions, not pre-counting predictions. His pre-election prediction was great, but no better than several others. I hope that next time he makes his "FINAL" predictions BEFORE the election, not while most of the polls are already open and info is filtering out.
Jim Lindgren
That's what comes with a sound understanding of probability and statistics.
But it still amazes me that supposedly intelligent people just can't wrap their minds around these concepts.
Just Monday I saw Kathryn Jean Lopez of National Review (remember, I said "supposedly intelligent people") implying some kind of shenanigans because Zogby's one-day, ~400 voter survey on Sunday had shown McCain up by one point, but Zogby's 3-day tracker (~1200 voters, the way the survey is supposed to work) ultimately showed a comfortable Obama lead on Monday.
Also, this analysis on whether Nate Silver said 5.9 or 6.1, or if he said it Tuesday morning or afteroon seems really like nit picking. His model is based on the pre-election polls, not the turnout or exit polls, and as part of his modeling process he makes 10,000 simulations. So these numbers really correspond to a range of possibilities.
I think the one thing we learned during this cycle is that the poll aggregators are MUCH better at predicting the election than any single poll.
(graph chart)
Obama - 63%, McCain, 37%
(pie chart)
Obama 46%, McCain, 56%
(another graph chart)
Obama 12%, McCain, 6%, Thinks that polling is an utterly useless way to try and gauge American thought, 82%
The exact language was funnier, sorry, I'm paraphrasing
Note: I have followed 538 and pollster obsessively throughout the campaign and think they are the best, most intelligent, empirical sites.