Obama Surge? Or Polling Error?
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James Joyner | Monday, January 7, 2008 |
Chris Sillizza believes Barack Obama “received a real New Hampshire boost from his win in Thursday’s Iowa caucuses.” His evidence for the surge:
In a new CNN/WMUR poll, Obama leads Sen. Hillary Rodham Clinton (N.Y.) 39 percent to 29 percent, a major change from the 33 percent tie that the same survey showed yesterday. A new USA Today/Gallup poll confirms the Obama bounce, putting him 13 points ahead of Clinton. A new Franklin Pierce/WBZ survey showed a more modest gain for Obama. He led Clinton 34 percent to 31 percent in the latest poll; four days ago he trailed Clinton 32 percent to 28 percent.
Most of these fluctuations are within the margin of sampling error in these polls. Remember, in a poll with a margin of +/-3 percent, 33 percent is really just a shorthand for a range of 30-36.
The outlyer is the CNN/WMUR poll. But I’m rather dubious of a shaft shift that dramatic in one day. If one looks at the poll results themselves, though, we see that they are using very small samples and tracking daily, resulting in a margin of +/-5 for the Democrats and +/-6 for the Republicans. And that’s with a confidence level of 95%, meaning one poll in 20 is likely to be a complete anomaly.
If one looks at more polls, though, and the trends over time, we see a pretty steady movement towards Obama that started well before Iowa voted.
Here are the most recent polls tracking Democrats, all of which screen for likely primary voters:
And here are the longer term trends:
So, yes, there has been an Obama surge and it has come mostly at the expense of Hillary Clinton. But, no, it doesn’t seem to be a reaction to the Iowa Caucuses.
About the Author: James Joyner is the publisher of Outside the Beltway and the managing editor of the Atlantic Council. He's a former Army officer, Desert Storm vet, and college professor with a PhD in political science from The University of Alabama. He lives just outside the Beltway in Alexandria, Virginia with his wife and infant daughter.
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"If one looks at more polls, though, and the trends over time, we see a pretty steady movement towards Obama that started well before Iowa voted."
But all the polls you list start on 1/4, the day after Iowa. And that uptick in the green line seems to be from right around Iowa (though it is hard to pick out the exact day on that graph).
Are there other data that might actually support your point?
Well, looking at the line graph, Obama has had a positive trend going since September.
And James: my initial response to the double-digit lead for Obama was skepticism/that it was an anomaly, yet it seems to be showing up in all the polls at this point.
I noted several here and here.
Zogby has a new one this morning with the same basic result.
that uptick in the green line seems to be from right around Iowa (though it is hard to pick out the exact day on that graph).
But it's only an uptick because it follows what appears to be a one-day anomaly wherein Obama plummets and Clinton surges. Otherwise, as Steven notes, it's been a steady trend since September.
Sorry, but I just couldn't resist pointing out this humorous typo in your post:
But I’m rather dubious of a shaft that dramatic in one day
Just gave me a chuckle while I'm here waiting in the airport lounge...
Heh. Fixed. -jhj
my initial response to the double-digit lead for Obama was skepticism/that it was an anomaly, yet it seems to be showing up in all the polls at this point.
Yup, my sense as well. He's leading big in most of the polls in the RCP chart, which are all in the last couple of days.
