Size of margin four or six points depending on turnout assumptions
PRINCETON, NJ -- Gallup Poll Daily tracking shows Barack Obama running ahead of John McCain among likely voters -- 50% to 46% using the "traditional" model Gallup has employed in past elections, and 51% to 45% using an "expanded" model that takes into account possibly greater turnout by new or infrequent voters.
These results are based on Oct. 20-22 polling and suggest preferences may be stabilizing for the moment, as the data for individual nights in the three-day rolling average for both likely voter models were quite similar. Obama's current advantage in both models is slightly smaller than what Gallup reported Tuesday.
The stability is also evident in registered voters' preferences, with Obama's lead among this group now 50% to 43%, with each individual night in the Oct. 20-22 average showing similar figures.
McCain's 43% share of the vote in today's rolling average among registered voters matches his October high, but is well below his 49% campaign peak, measured just after the Republican National Convention. (To view the complete trend since March 7, 2008, click here.) -- 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. 20-22, 2008. For results based on this sample of 2,788 registered voters, the maximum margin of sampling error is ±2 percentage points.
For results based on the sample of 2,399 "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 1,821.
For results based on the sample of 2,349 "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.