PRINCETON, NJ -- Gallup Poll Daily tracking data indicate that about 11% of registered voters who plan to vote have already voted as of Wednesday night, with another 19% saying they plan to vote before Election Day. Roughly equal percentages of Barack Obama supporters and John McCain supporters have taken advantage of the early voting opportunity -- so far.
In addition to the 11% who say they have already voted, another 19% of registered voters who plan to vote say they will vote early, before Election Day. That leaves just about 7 out of 10 voters who intend to go to the polls on Nov. 4 itself.
The percentage of early voters has increased from 7% in Gallup's Friday through Sunday average, when Gallup first began measuring this variable, to the current 11% in the Monday through Wednesday average.
The pace of early voting so far appears to be roughly on par with 2004. At about this time before that year's election -- Oct. 22-24 -- 9% of registered voters said they had already voted. However, in that 2004 poll, only an additional 13% said they intended to vote early, lower than the 19% who say so in the current Oct. 20-22 average. Thus, early voting this year may end up being higher than it was in 2004. (In Gallup's final poll before the election that year, conducted Oct. 29-31, 17% said they had voted early, and another 4% claimed they were still going to vote before Election Day.) As noted above, projections from this year's data are that as many as 30% of voters could end up voting early.
The impact of early voting on the election outcome is difficult to determine. Having the results for early voters "locked in" means that a last-minute surge in support toward either candidate would not be reflected in the final election outcome for those early voters.
At this point, there is little significant difference in the propensity to vote early between the Obama supporters and the McCain supporters interviewed in the aggregated sample of all interviews conducted from last Friday through Wednesday (among whom an average of 9% said they had already voted).
Obama has been ahead in Gallup Poll Daily tracking conducted while these data were being gathered. Thus, while equal percentages of Obama and McCain voters have voted early, there are more of the former than of the latter, meaning that early voting generally reflects the same Obama lead evident in the overall sample. Thus, if McCain gains rapidly in the days left, Obama benefits, since Obama can't lose votes he has already received. If McCain loses support rapidly, Obama will not have the chance to pick up even more support from those who have already voted.
There is a slight tendency for early voting to skew older. Early voting ranges from 14% of voters 55 and older (in aggregated data from Friday through Wednesday) to 5% of those under age 35. Plus, another 22% of voters aged 55 and up say they plan to vote early, meaning that by Election Day, over a third of voters in this older age group may already have cast their ballots.
There is also a significant difference in early voting by region of country. Voters in the West are the most likely to say they have voted already and to say that they plan to vote early, before Election Day. Voters in the East are least likely to be early voters.
Results are based on telephone interviews with 2,717 registered voters, aged 18 and older, conducted Oct. 20-22, 2008. For results based on the total sample of voters, one can say with 95% confidence that the maximum margin of sampling error is ±3 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.