PRINCETON, NJ -- President Barack Obama got a modest bump in support immediately after last week's Democratic National Convention, with 50% of registered voters now saying they would vote for him if the election were held today, up from 47% before the convention. With the concomitant two-point drop in Mitt Romney's support, Obama's advantage has expanded from one percentage point to six points.
These results are based on a comparison of Gallup Daily tracking interviews conducted Aug. 31-Sept. 3 and Sept. 7-10. The Democratic convention was held Sept. 4-6 in Charlotte, N.C.
Obama's three-point gain in voter support after his party's nominating convention is below the historical average of five points, and similar to his four-point bounce in 2008. However, it was a better showing than Romney had this year, as the Republican nominee received no increase in support after the GOP convention.
The pattern of lackluster convention bounces this year is reminiscent of the 2004 campaign, when John Kerry challenged incumbent George W. Bush for the presidency. Bush had approval ratings similar to Obama's, near 50%. Kerry and Bush were essentially tied for much of the campaign. Kerry received no bounce from his convention, while Bush got a small bounce, which propelled Bush into a lead after the two had been essentially even during most of the campaign.
More generally, convention bounces have been smaller in recent years, averaging 3.8 points per candidate since 1996 after averaging 6.2 points from 1964-1992. And in the five elections since 1996, two candidates (Romney and Kerry) got no convention bounce, and all but three of the 10 candidates (Bush and Gore in 2000 and McCain in 2008) received bounces that were no greater than the historical average of five points.
Obama Builds a Lead Over Romney
As a result of the changes in voter support after the 2012 Democratic convention, Obama has moved ahead of Romney. Obama's current six-point lead in Gallup's reported seven-day rolling average (including the three days of the Democratic convention and the four days afterward) is one point below his high of seven points in late April. Romney has led by as many as five points, shortly after he clinched the nomination in mid-April.
The race has been close for most of the time since Romney clinched the Republican nomination, with Obama and Romney each averaging 46% support since then.
Obama Approval Also Up
Obama's job approval average, based on Gallup's three-day rolling averages, also increased following the convention to 50%, after being at 45% just before the convention. Obama's approval rating reached as high as 52% during the convention, the highest it had been since May 2011, after the death of Osama bin Laden.
Although Obama's convention bounce was modest, the fact that Romney got no bounce certainly means the president came out ahead after the back-to-back party conventions. For now, Obama has established a lead among registered voters. Differences in voter turnout among Obama and Romney supporters, which usually work to the benefit of the Republican nominee, could cut into Obama's lead. In the last three presidential elections, voter turnout has reduced the Democratic advantage in Gallup's final pre-election poll by two to four percentage points. Thus, if Obama maintains a five- to six-point lead among registered voters, he would be in a strong position to win, barring some unusual surge in Republican turnout this year.
Gallup will begin to track the preferences of likely voters in October.
Results for this Gallup poll are based on telephone interviews conducted Sept. 7-10, 2012, on the Gallup Daily tracking survey, with a random sample of 1,896 registered voters, aged 18 and older, living in all 50 U.S. states and the District of Columbia.
For results based on the total sample of registered voters, one can say with 95% confidence that the maximum margin of sampling error is ±3 percentage points.
Interviews are conducted with respondents on landline telephones and cellular phones, with interviews conducted in Spanish for respondents who are primarily Spanish-speaking. Each sample includes a minimum quota of 400 cell phone respondents and 600 landline respondents per 1,000 national adults, with additional minimum quotas among landline respondents by region. Landline telephone numbers are chosen at random among listed telephone numbers. Cell phone numbers are selected using random-digit-dial methods. Landline respondents are chosen at random within each household on the basis of which member had the most recent birthday.
Samples are weighted by gender, age, race, Hispanic ethnicity, education, region, adults in the household, and phone status (cell phone only/landline only/both, cell phone mostly, and having an unlisted landline number). Demographic weighting targets are based on the March 2011 Current Population Survey figures for the aged 18 and older non-institutionalized population living in U.S. telephone households. All reported margins of sampling error include the computed design effects for weighting and sample design.
The questions reported here were asked of a random half-sample of respondents for four nights on the Gallup Daily tracking survey.
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.
For more details on Gallup's polling methodology, visit www.gallup.com.