PRINCETON, NJ -- Last week's Republican National Convention had a minimal impact on Americans' self-reported voting intentions, with just about as many saying the convention made them less likely to vote for Mitt Romney as say it made them more likely to vote for him.

These results, based on Gallup Daily tracking conducted Aug. 31-Sept. 1, showed predictable partisan differences. Republicans overwhelmingly said the convention made them more likely to vote for Romney, although most would likely be voting for their nominee anyway. Democrats as predictably said the convention made them less likely to vote for Romney. Independents, a key group in any presidential election, were essentially split, with 36% saying the convention made them more likely to vote for Romney and 33% less likely -- although 30% said they don't know or that the convention made no difference.

Gallup has asked this question after selected conventions going back to 1984. Although the question was asked at differing time intervals after the conventions and in different survey contexts, the results give a rough approximation of the conventions' relative impact.

This historical context shows that the 2012 GOP convention generated about the same impact as the two previous Republican conventions -- in 2008, when John McCain was nominated for president, and in 2004, when George W. Bush was re-nominated.

The net impact of each convention can be calculated by subtracting the percentage who said the convention made them less likely to vote for the party's nominee from the percentage saying it made them more likely to vote for him. This year, the net impact of the GOP convention was +2. This compares with +5 and +3 for the GOP conventions in 2008 and 2004, respectively.

The relationship between Americans' reports of whether the convention affected their vote and the final outcome of the election is mixed.

Barack Obama's Democratic convention in 2008 generated a net impact score of +14. Obama, of course, went on to win in November 2008 by a seven-percentage-point margin in the popular vote.

But John Kerry's Democratic convention in 2004 also had a net impact score of +14, significantly higher than the +3 of 2004's Republican convention. Kerry, however, lost the election to Bush, the Republican nominee.

The 1992 Democratic convention generated the largest net impact in Gallup's records; at that time, 60% of Americans said it made them more likely to vote for Bill Clinton and 15% said it made them less likely. Clinton won the popular vote in 1992 by 5 ½ points.

Americans were also quite positive on a relative basis after the Democratic convention in 1988, in which Michael Dukakis was nominated. But Dukakis went on to lose in November of that year.

Romney's Acceptance Speech Receives Low Marks

Romney's acceptance speech this year scored low by comparison to previous convention speeches going back to 1996. Thirty-eight percent of Americans rated the speech as excellent or good, while 16% rated it as poor or terrible. The 38% who rated the speech as excellent or good is the lowest rating of any of the eight speeches Gallup has tested since Bob Dole's GOP acceptance speech in 1996.

Obama's 2008 speech was the most warmly received of the eight speeches Gallup has evaluated using this measure -- 58% of Americans rated it as excellent or good. Americans evaluated McCain's speech in 2008 less positively, but at 47% excellent or good, it was still more highly rated than Romney's this year.

As is the case for Americans' evaluations of the conventions' impact, their evaluations of speeches do not necessarily presage victory in November. Obama's speech was more highly evaluated in 2008 than McCain's, and Obama went on to win. Kerry's and Bush's 2004 speeches were equally highly evaluated, but Bush won the election.

Self-Reported Viewing of Convention Low This Year

Americans today get their news and information about events like political conventions from a number of sources. Many do not watch the conventions live on television, but may see bits and pieces later on the Internet or on other broadcast or cable programs. Reinforcing this, the 51% of Americans who said they watched "a great deal" or "some" of the convention on TV is the second-lowest for any of the eight conventions Gallup has asked about going back to 1996.

Only the Republican convention in 1996 was viewed on TV by fewer Americans. The most watched of the eight based on this measure was the 2008 Republican convention in which McCain was nominated for president and Alaska Gov. Sarah Palin was confirmed as the Republicans' vice presidential nominee.

Implications

Americans' immediate reactions to the Republican convention do not by themselves predict who is going to win in November. That is particularly true at this point in the election campaign, given that there is not yet any comparative information from the Democratic convention, which gets underway in Charlotte on Sept. 4.

Still, these preliminary data show that both the self-reported impact of the convention and the evaluation of Romney's speech are at the bottom of the scale of comparable evaluations from recent conventions.

Gallup Daily tracking data through Sept. 1 show no change in the positioning of the two candidates when Americans are asked for whom they would vote if the election were held today. Thus, Americans' relatively weak reaction to the Republican convention does not appear to have hurt their likelihood of voting for Romney so far, although it apparently is related to the lack of a typical convention bounce.

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