As we get closer to the final weekend of the presidential race there’s still no trend that can be determined by looking at all the polls, no one candidate moving to a small but significant lead. Despite that, most supporters of President Obama and challenger Mitt Romney feel confident, enthused by polls they can point to showing their candidate in good shape. Call it the “Gallup” versus “Silver” debate.
You can read an interesting article about the competing polls here. The ways pollsters are projecting turnout is the main reason for the divergence. The “Gallup” model, which represents the pollster firm and a few other polls, notably Rasmussen, assumes that the percentage of Republican and Democratic voters will be about the same. Gallup, in fact, believes a thin plurality will be Republicans. This is the reason why Gallup’s national sampling has shown Romney leading by 4 to 7 percent and Rasmussen’s state samples show many statistical ties or narrow Romney leads.
On the other hand, the “Silver” sample (in honor of Nate Silver, a NY Times poll statman who has consistently pegged Obama as the likely winner) assumes that substantially more Democrats, perhaps 7 to 9 percent, will vote compared to Republicans. Most media polls are assuming this percentage difference that favors Democrats. That produces national polls that show the race dead even or a narrow lead for President Obama. This turnout model also produces small but solid leads for the president in many key states, such as Ohio.
The “Gallup” model more closely follows the voting patterns of 2004 and 2010. The “Silver” model follows the 2008 voting model, when Democrats had 8 percent more voters than Republicans. As the above-linked article mentions, there are disagreements between both parties over the final voting numbers of various demographics, including minority voters, white voters, and young voters. One thing that most seem to agree with is that Republicans have the edge with voters who describe themselves as independents. That’s a change from 2008.
On Tuesday night, it’s a good bet that either the “Gallups” or the “Silvers” are going to feel let down by their political prognasticators. On the other hand, if the truth is somewhere in the middle, we could be settling down to a virtual tie with the resulting outcry and legal battles. Frankly, I want a definitive result, be it “Gallup” or “Silver.”