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Morning Status Update for 10/17


We logged 21 new statewide polls yesterday, including 9 of the controversial Zogby Interactive surveys conducted online using a non-random panel of Internet volunteers. The overall pattern of the new polls is roughly the same as we have seen in recent days. Most confirm the gains registered by the Democrats since September, although the net impact on our trend estimates over the last 24 hours is mostly negligible. The exception is Ohio where two new surveys, including one from Zogby, narrow our trend estimate enough to shift that state and its 20 electoral votes from lean Obama back to our toss-up category.

Most of these polls follow-up on previous surveys from the same pollster conducted in September or earlier, and as such, most confirm the recent gains by the Obama-Biden ticket. Only three of the the new surveys track results gathered earlier in October, two of those show a slight shift to Obama, one shows a slight shift to McCain.

081017 daily.png

Virtually all of the interviews in the national tracking surveys posted yesterday were conducted before the Wednesday night debate. Today's releases will be the first to indicate whether the debates made any noticeable dent in vote preference nationally. Please note that for the rolling-average tracking polls, the table above lists the previous non-overlapping sample for each pollster, not the release from the previous day.


081017 trends.png

The new surveys moved our trend estimates in both directions in the closer battleground states. In five states, Missouri, North Carolina, North Dakota and Virginia, the estimates shifted slightly in Obama's direction. In five states, Colorado, Florida Indiana, Nevada and Ohio, the estimates moved slightly in McCain's direction.

A new poll in North Dakota sponsored by a Democratic affliated union, only the second public poll released their in a month, confirms the very close result obtained by the The Forum there earlier this week and solidifies our surprising "toss-up" status for that state.

Two new surveys in Ohio were from Rasmussen (showing a 49% to 49% tie) and Zogby Interactive survey (showing McCain leading, 50% to 45). These narrow Obama's lead on our Ohio trend estimate by nearly two points, enough to shift Ohio back to the toss-up category. Our estimate shows Obama leading McCain by two and a half points (49.0% to 46.5%)

Ohio is the one state where -- for the moment at least -- our inclusion of the Zogby surveys affects the classification. If we use the "filter" tool on our charts to remove the Zogby surveys from the trend estimate (as in the modified chart above), Obama's lead widens by about a point (to 49.6% to 45.8%), which would have left Ohio in the lean Obama column.

All of which raises the question of how Internet panel surveys like Zogby's work and why we include them. The short version is that Zogby, like most companies doing survey research online draws, a sample from a non-random panel of volunteers that have agreed to complete surveys online. They then attempt to weight the completed interviews to match the demographics and partisanship of the electorate. (Interests disclosed: Pollster.com receives financial support from YouGov/Polimetrix, another company that conducts internet panel surveys).

Despite the hype on their website, the Zogby Interactive surveys have produced results of dubious accuracy. Following the 2006 elections, the Wall Street Journal's Carl Bialik found that Zogby's online surveys "missed by an average of 8.6 percentage points" in U.S. Senate races, "at least twice the average" of results from four other pollsters he examined, SurveyUSA, Rasmussen and Mason-Dixon. The Zogby Interactive surveys also rank second to last on Nate Silver's computations of "pollster introduced error," earning an error rate (5.73) more than double the average (1.97). Charles Franklin also noted some odd patterns in their national trial heat results in late 2007.

So why include them here? Our philosophy since launching Pollster.com two years ago has been to include all polls, good, bad and ugly. We do so partly to provide a reference and record of all polls, and partly because the loess regression trend lines usually resist the influence of "outlier" results from a single pollster (Charles Franklin discussed this issue at length here). And finally, we have worked hard to provide interactive charts that allow you to filter out individual pollsters to check for instances where one poll or one pollster may have a disproportionate impact on our perceptions of where the race stands.

 

Comments
1magine:

The Rasmussen Reports daily Presidential Tracking Poll for Friday shows Barack Obama attracting 50% of the vote while John McCain earns 46%. These figures reflect a remarkably stable race in which Obama has enjoyed a four-to-eight point advantage for twenty-two straight days. The last time McCain was up by even a single point was one month ago today (see trends).

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joelspolls:

Mark,

Correct me if I'm wrong, but doesn't Polimetrix recruit its panel using standard RDD methods? If so, that puts them in an entirely different category from Zogby's convenience sample which has absolutely no statistical merit whatsoever. In my previous work on election poll reliability, I found that Polimetrix surveys were very reliable and Zogby's online surveys were far worse than those of any other firm out there. I appreciate your and Charles' decision to be inclusive about which surveys to include. But frankly, I don't think Zogby's online surveys (as distinct from his telephone surveys) even merit the term "survey." They are "pseudo-polls" or "straw polls" and don't belong in the same category with surveys that, however mediocre some might be (like Zogby's phone surveys), at least are based on scientific sampling methods.
-- Joel

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Sean:

honestly im thankful for outliers like zogby that lean republican, they keep obama supporters from getting complacent, expecting a landslide victory, and possibly causing them to not show up and vote on the 4th of November.

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drdr:

Current toss-up states include ND, NC, WV, IN. This is a very difficult map for Sen. McCain. To win, he will have to improve his national standing by 4-5 points and then still thread the needle with all of the Bush states except IA, NM, NH.

Sen. Obama still may be holding back his Oct. fundraising to blunt any momentum developed by Sen. McCain. Also a possible Gen. Powell endorsement of Sen. Obama on MTP Sunday would not be helpful for Sen. McCain. National polls will continue to tighten, but Sen. McCain is really running uphill.

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jatchwa:

I appreciate your explanation for including Zogby polls. You're wrong, but I appreciate hearing an explanation.

I have a poll that say Obama is winning South Carolina 85 percent to 10 percent, 5 percent undecided. Please include this in your averages.

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I agree that the Zogby interactive polls should be excluded. I think you have done your best to ratify them under very real, empirical conditions and they don't work out. Given the hoopla that Zogby has on his site, I think a challenge is in order to balance things out and raise some appropriate skepticism.

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DTM:

I think the best approach to this issue is something like Nate Silver's weighting scheme. But I am not sure Pollster can follow that approach without making more judgment calls than would fit with their philosophy, and it does seem like a next-best solution is the interactive charts (letting people exclude Zogby Interactive if they so desire).

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nataraj:

Here is an idea.

Exclude Zogby from front page numbers/charts. let people "include" them if desired.

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With both Maine and Nebraska allocating electoral votes on the basis of congressional districts, are there any polls that go down to this level in these states? I have a feeling, with McCain going to Maine, that one electoral vote might make the difference.

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douglasdao:

The right-wingers may now whine and stamp their little feet in protest of the polls showing a swing to Obama.

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It's difficult to imagine that four years ago at this time we were focusing almost solely on Ohio, Pennsylvania, Michigan and Florida. Instead, now it's "Missouri, North Carolina, North Dakota, Virginia, ... Colorado, Florida Indiana, Nevada and Ohio." What these nine states have in common no doubt has anyone supporting McCain terrified, resigned, depressed or begging God for a miracle.

See who's been inducted into the Hypocrites Hall of Infamy.

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