Past Gallup performance - the only big miss was 1992, when they missed by 6 (assigning too much of Perot vote to Clinton). In 1996, 2000, 2004 they were within 3% from the correct margin.
******************
2004 Final Poll (Actual)
Bush 49 (50.7)
Kerry 49 (48.2)
2000 Final Poll (Actual)
Bush 48 (47.9)
Gore 46 (48.4)
1996 Final Poll (Actual)
Clinton 52 (49.2)
Dole 41 (40.7)
Perot 7 (8.4)
1992 Final Poll (Actual)
Clinton 49 (43)
Bush 37 (37.5)
Perot 14 (18.9)
1988
Bush 56 (53.4)
Dukakis 44 (45.7)
1984
Reagan 59 (58.7)
Mondale 41 (40.6)
Gallup finally mentioned their party affiliation numbers in the article associated with their final poll. Here are those numbers:
Democrat - 39%
Independent - 31%
Republican - 29%
Here are the numbers from exit polling in the 2004 election:
Democrat - 37%
Republican - 37%
Independent - 26%
Here are the numbers from exit polling in the 2006 election:
Democrat - 38%
Republican - 36%
Independent - 26%
Do they really believe that the gap has gone from 0 in 2004 to +2 for the Democrats in 2006 to +10 for the Democrats in 2008?
Do YOU believe that?
-Bob
In other words, they are expecting that BHO will cause an unprecedented shift in the composition of the electorate.
That's why they are essentially assuming that 13 million more Dems will vote in this election than Pubs (130 million voters * 10 point Dem weighting advantage in their polls).
Not likely. Not even close, because there are strong indications that GOP turnout will grow significantly, maybe even more than the pro-Obama turnout. So, this poll is garbage.
I guess this'll be their next big miss year, because there is no way that Obama is going to win this thing 55%-44%.