Are GOP voter purges skewing the poll numbers? I read the
BuzzFlash interview with Greg Palast posted by
struggle4progress, and it occurred to me that all the major polls sample registered voters and likely voters. And, there is a distinction between the two.
Then it occurred to me that the pollster really has no way of knowing if someone is or is not a registered voter and therefore a likely voter. A person being polled self-identifies that they are or are not registered. This has massive implications for Obama's the current poll numbers. In a battleground state like Colorado, where
this morning's Washington Post has Obama with a 9 point lead. The Colorado poll was of 1,088 likely voters. And according to Palast, 19.4% of all registered voters in Colorado have been purged.
The WAPO article doesn't state the methodology and maybe it's posted somewhere, but I don't know where and I still haven't had enough coffee. So let's make some assumptions. Let's assume the poll was weighted 35% Democrat, 30% Republican and 35% other. Polls seem to be structured approximately pretty much like that.
Data from the Quinnipiac University on this poll shows that candidate support breaks down as:
Democrats Republican Other
Obana 93% 6% 51%
McCain 4% 89% 40%
DK/DC 3% 5% 9%
Obama/McCain. From these numbers we get:
Obama 354 20 194 568
McCain 15 290 152 458
DK/DC 11 16 34 62
381 326 381 1088
Now, 19.4% of all voters in CO have been purged from the rolls. Let's assume that 80% of the purged voters were Democrats, 5% were Republican and 10% were Independent or other (sounds reasonable to me). That means that the actual number of sampled Democrats in the Colorado poll after the purge would be:
Democrats Republican Other Total
Aft Purge 212 316 360 887
Sample % 24% 36% 41% 100%
Difference 169 11 21 201
% Diff 44% 3% 6% 18%
Now we have a poll where Democrats were
under sampled. However, the same numbers of voters would turn out to vote because they didn't know they were purged. Assuming no one knows they were purged or else they would not have told the pollster that they were registered, 44% of Democrats would not be allowed to vote.
Using the same preference percentages as above, the new breakdown would be:
Democrats Republican Other Total Percentage
Obama 197 19 183 400 45.0%
McCain 8 281 144 433 48.8%
Other 6 16 32 55 6.1%
887
We would then see that McCain squeaked by in a 48.8% - 45.0% victory in Colorado. Even if you reduce the percent of the 19.4% purged to 60% Democrat, 5% Republican and 35% Indy, the results are a 47.2% - 47% McCain win. They will call him the Comeback Kid, just as he did in the primaries. Something smells real bad here.
Check my numbers, I think they're correct. Maybe my methodology is off. I've had plenty of coffee now so I think they're correct.