Gallup Daily: Obama’s Lead Widens Some on All Bases Advances to 8-point lead among “traditional likely voters”

PRINCETON, NJ -- The political landscape could be improving for Barack Obama in the waning days of the campaign. Gallup Poll Daily tracking from Oct. 28-30 shows him with an eight percentage point lead over John McCain among traditional likely voters -- 51% to 43% -- his largest margin to date using this historical Gallup Poll voter model.

Since Tuesday, McCain's support among traditional likely voters has dropped by four points (from 47% to 43%), Obama's has risen by two points (from 49% to 51%), and the percentage of undecided voters has increased from 4% to 6%.

Thursday night's interviews are the first conducted entirely after Obama's widely viewed 30-minute prime-time campaign ad, which ran on several television networks Wednesday evening. Obama held a substantial lead over McCain in last night's polling, however no greater than what Gallup found on Wednesday.

Obama's lead among expanded likely voters is only slightly greater than that seen among traditional likely voters. He now leads McCain by nine-points, 52% to 43%, using this looser definition that does not factor in whether respondents have voted in past elections, but strictly relies on their reported level of interest and intention to vote in the 2008 election.

Obama's current 11-point lead over McCain among all registered voters -- 52% to 41% -- is up from an eight-point lead in yesterday's report, and ties his highest advantage on this basis, last recorded 10 days ago. (To view the complete trend since March 7, 2008, click here.)

Obama's favorable position among traditional likely voters in the latest polling is partially reflective of his strong position among all registered voters. However, at other times when Obama has led McCain by 11-points among registered voters, his likely voter advantage has been lower than it is now, in the five- to seven-point range. Thus, Obama's improved likely voter standing also reflects a higher turnout propensity for his supporters than what Gallup has seen at earlier times this month. This could stem from the superiority his well-funded campaign appears to have over the McCain campaign in contacting his supporters to get out and vote. -- Lydia Saad

(Click here to see how the race currently breaks down by demographic subgroup.)

Survey Methods

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. 28-30, 2008. For results based on this sample of 2,825 registered voters, the maximum margin of sampling error is ±2 percentage points.

Results based on "traditional" likely voters (based on the model taking into account current voting intention and past voting behavior) include interviews with 2,116 voters, and assume a turnout of 60% of national adults. The likely voter sample is weighted to match this turnout assumption, so the weighted sample size is 1,844. The associated maximum margin of sampling error is ±3 percentage points.

For results based on the sample of 2,459 "expanded" likely voters (based on the model taking into account current voting intention 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 land-line telephones (for respondents with a land-line 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.