The survey results are based on telephone re-interviews conducted November 5 – 8, 2004 among 1,209 voters under the direction of Princeton Survey Research Associates International. (“Voters” are those respondents who said they voted in the 2004 election.) This sample was selected from those identified as registered voters in two previous nationwide surveys of adults 18 years of age or older, the first conducted Early October 2004 and the second in Mid-October 2004. For results based on the total sample of voters, one can say with 95% confidence that the error attributable to sampling and other random effects is plus or minus 3.5 percentage points.
In addition to sampling error, one should bear in mind that question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of opinion polls.