PRINCETON, NJ -- Gallup Poll Daily tracking from Friday through Sunday gives Barack Obama an 11 percentage point lead over John McCain in the presidential vote preferences of all registered voters, 52% to 41%.

Although the absolute percentages supporting Obama and McCain have varied in a narrow range for nearly the past three weeks, Obama's lead shrank to six points late last week, only to expand again in recent days. (To view the complete trend since March 7, 2008, click here.)

Gallup's latest three-day rolling average, from Oct. 17-19, spans a weekend when McCain's running mate, Alaska Gov. Sarah Palin, drew a huge television audience and much post-show media coverage for her cameo appearance on NBCs "Saturday Night Live." Also, on Sunday former Secretary of State and chairman of the Joint Chiefs of Staff, Gen. Colin Powell, delivered a strong endorsement of Obama for president -- calling his candidate "a transformational figure" who is capable of being "an exceptional president."

The Gallup Poll Daily tracking poll shows no shift in support for the candidates between Saturday and Sunday to suggest that either of these events had any immediate impact on voter preferences.

Gallup's modeling of likely voters indicates the race is somewhat tighter if we assume that voter turnout patterns will be similar to those seen in most presidential elections from 1952 through 2004. Using this "traditional" definition of likely voters, which takes into account respondents' history of voting as well as their current interest in the campaign and self-reported likelihood of voting, Obama leads McCain by five points, 50% to 45%. This is slightly better than the two- to three-point leads he held among this group late last week.

An alternative expanded likely voter model shows what would happen if turnout reflects voters' self-reported likelihood of voting and campaign interest, but is not assumed to be dependent on their voting history. Under that scenario, Obama leads by 9 points, 52% to 43%. -- 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. 17-19, 2008. For results based on this sample of 2,774 registered voters, the maximum margin of sampling error is ±2 percentage points.

For results based on the sample of 2,340 "traditional" likely voters (based on the model taking into account current voting intention and past voting behavior), the maximum margin of sampling error is ±2 percentage points.

For results based on the sample of 2,271 more broadly defined likely voters (based on the model taking into account current voting intention only), the maximum margin of sampling error is ±2 percentage points.

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.