PRINCETON, NJ -- Barack Obama holds a statistically significant lead over John McCain in both Gallup likely voter models, according to Oct. 27-29 Gallup Poll Daily tracking. In the traditional model, which defines likely voters based on current voting intention and past voting behavior, Obama holds a 50% to 45% lead. In the expanded model, in which only current voting intentions are considered, his lead is 51% to 44%.
As in any election, the final outcome, in large part, hinges on who turns out to vote and who does not. If all registered voters participated, Obama would probably win comfortably. He leads McCain by 50% to 42% in the latest estimate of registered voter preferences, and has averaged a nine percentage point lead since Oct. 1. (To view the complete trend since March 7, 2008, click here.)
Both likely voter models currently show a slightly closer race than is evident in the registered voter estimate. Obama has never trailed in either likely voter model since Gallup began tracking likely voter preferences in early October, averaging a four-point lead using the traditional model and an eight-point lead using the expanded model.
Just five days remain until Election Day, and McCain and the Republicans are campaigning hard in key states to try and change Obama's lead. Late comebacks are rare, but have occurred, including Harry Truman in 1948 and Ronald Reagan in 1980. -- Jeff Jones
(Click here to see how the race currently breaks down by demographic subgroup.)
For the Gallup Poll Daily tracking survey, Gallup is interviewing no fewer than 1,000 U.S. adults nationwide each day during 2008.
The general-election results are based on combined data from Oct. 27-29, 2008. For results based on this sample of 2,800 registered voters, the maximum margin of sampling error is ±2 percentage points.
For results based on the sample of 2,078 "traditional" likely voters (based on the model taking into account current voting intentions and self-reported past voting behavior), the maximum margin of sampling error is ±3 percentage points. The traditional likely voter model assumes a turnout of 60% of national adults. The likely voter sample is weighted to match this assumption, so the weighted sample size is 1,825.
For results based on the sample of 2,437 "expanded" likely voters (based on the model taking into account current voting intentions only), the maximum margin of sampling error is ±2 percentage points. The expanded likely voter model does not make any assumptions about turnout level.
Interviews are conducted with respondents on landline telephones (for respondents with a landline telephone) and cellular phones (for respondents who are cell phone only).
In addition to sampling error, question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of public opinion polls.