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Final Poll: Obama 55%, McCain 44%, Other 1%

Gallup: Party Weights 39% Dem, 31% Independent, 29% Republican

Obama pary share: 91% dem, 9% rep, 48% indep

McCain party share: 91% rep, 9% dem, 43% indep

Undecided party share: 9% indep

Obama Support: 91% Democrat(91% x 39% party weight =35.49%), 48% Independent (48% x 31% Independent weight= 14.88%), 9% Republican (9% x 29% party weight=2.61%

35.49% + 14.88% + 2.61% = 52.98%...2.02% short of the 55% Gallup gave Obama. Where did they get the other 2.02%? Must have come from the 9% left of independents.

McCain Support: 91% Republican (91% x 29% party weight =26.39%, 43% Independent (43% x 31% party weight=13.33%, 9% Democrat (9% x 39% party weight=3.51%)

26.39% + 13.33% + 3.51% = 43.23%...0.77% short of the 44% given to McCain in the final poll.

So now let’s allocate the 9% undecideds (according to Gallup) to get to the final result. As we said, Obama needs 2.02% more accounted for while McCain needs 1.16% accounted for. 2.02%/31% (indep party weight)= 6.52% indep.

McCain: 1.16%/31% (indep party weight)= 3.75%

6.52% + 3.75% adds up to 10.27%, more than the 9% we said was unallocated. Gallup must have rounded the final results. We’ll just say Gallup gave Obama 6% to McCain’s 3% of the remaining independents. So they basically gave Obama a 2-1 break of the remaining undecided independents while he only got 48% of the decided vote. It’s much more likely that the undecideds break 2-1 for MCCAIN. That’s outrageous point number 1 we’ll make in this post.

Ok, bear with me now. Final Gallup breakdown is Obama: 91% dem, 9% rep, 54% indep (48+6 undecided allocation)

McCain broke down as follows: 91% rep, 9% dem, 46% indep. (43+3 undecided allocation)

There is a statistical noise of 1% for Barr and Nader, etc. Let’s just assume, for the sake of easy calculations that you can subtract 1% from any final result Obama gets in my model.

Now, let’s reweight to 38% dem, 34% rep, 28% indep just for the sake of argument. You can run your own allocations that you like better. Let’s also give McCain undecideds 2-1, resulting in 51%-49% independent advantage for Obama.

Obama: 91% dem (91% x 38% party weight)= 34.58%, 9% rep (9% x 34% party weight) = 3.06%, 51% ind (51% x 28% party weight) = 14.28%

34.58% + 3.06% +14.28% = 51.92%

McCain: 91% rep (91% x 34% party weight)= 30.94%, 9% dem (9% x 38% party weight) = 3.42%, 49% indep (49% x 28% party weight) = 13.72%

30.94% + 3.42% + 13.72% = 48.08%

So under this model we have Obama 51.92%-48.08%. We have just explained away a 4% increase for McCain and 3% decline for Obama by re-weighting the party IDs and reallocating undecided independents from 2-1 for Obama to 2-1 for McCain (which seems much more likely).

If undecided independents break for McCain 3-1 you get this result: Obama 51.71%-48.29%.

What I would be extremely interested to know is how Gallup allocated ALL undecideds. I was able to extract by calculation the approximate break down of undecided independents, and it shows a 2-1 break for Obama. I find that extremely unlikely. What I cannot calculate from the available information is how ALL undecideds broke. If Gallup gave Obama a 2-1 break of ALL undecideds then that further skews the poll. If that’s the case then you could easily turn that around to a 2-1 break for McCain and then this is at worse a dead heat if not a McCain lead using a more realistic party ID breakdown.

Conclusion and what we already knew anyway, Gallup skewed this poll hugely in Obama’s favor and it has just been debunked as unscientific.