In the kitchens of the Associated Press, it's almost as if the wire service asked its chief cook -- er, pollster -- GfK Roper Public Affairs and Media, to do the following:
- Whip up a tasty, representative poll after the Republican Convention.
- Three weeks later, make the same dish, but this time adjust the mix of ingredients by radically oversampling Democrats and undersampling Republicans, thereby creating a false illusion of momentum in the campaign of Barack Obama, and of decline in John McCain's.
- Hope people don't notice the changes in the recipe.
Of course we don't know if the differences between AP-CfK's Sept. 5-10 and Sept. 27-30 results were created deliberately, but the results sure look suspicious (both polls are available at PDF links found at AP-GfK's home page).
The more recent poll shows Obama with a 7-point lead among likely voters, both with and without leaners; the earlier poll showed McCain with a 5-point lead with leaners, and 4 points without.
Almost all of this 12-point swing (11 points with leaners) is more than likely almost completely due to major differences between the two polls' samples:
"Somehow," the sample make-up changed from 33-31 Democrat to 40-29 Democrat from the earlier to the latter poll -- a shift of nine points.
"Somehow," the Strong-Dem vs. Strong-GOP difference went from nothing to eight points.
"Somehow," the Strong-GOP vs. Moderate-GOP mix went from +3 to -3, a swing of six points.
Here's my best estimate of how the Sept. 27-30 poll would have turned out if AP-GfK had used a sample similar to the one it used Sept. 5-10:
After correcting for differences in the samples, almost all of Obama's double-digit pickup disappears, leaving McCain with four- and three-point leads without and with leaners, respectively. Even if one argues that the first poll showed a too-small gap between the two parties in the number of people sampled, substituting the 5-point difference Gallup identified shortly after the GOP convention would still leave McCain with a slight lead.
Either AP isn't supervising its GfK cooks properly, or it's directing them to poison discussions of presidential race, while hoping that no one notices the rancid product it is clearly producing.
AP waitress -- er, reporter -- Liz Sidoti brought out the new poll's results for our consumption yesterday with this exultant intro:
Barack Obama has surged to a seven-point lead over John McCain one month before the presidential election, lifted by voters who think the Democrat is better suited to lead the nation through its sudden financial crisis, according to an Associated Press-GfK poll that underscores the mounting concerns of some McCain backers.
Likely voters now back Obama 48-41 percent over McCain, a dramatic shift from an AP-GfK survey that gave the Republican a slight edge nearly three weeks ago, before Wall Street collapsed and sent ripples across worldwide markets.
As you can see above, her celebration is founded on fabrication; thus, her "explanations" are deep-fried in deception.
Just because AP, GfK, and Sidoti are serving us this rotten recipe doesn't mean that readers have to swallow it. So don't.
Cross-posted at BizzyBlog.com.