Results for the survey are based on telephone interviews conducted under the direction of Princeton Survey Research Associates among a nationwide sample of 1,206 adults, 18 years of age or older, during the period September 19 – 22, 1998. The interviewing was conducted in two waves: 500 interviews were conducted Saturday, September 19 and Sunday, September 20, the weekend preceding the release of Bill Clinton’s videotaped grand jury testimony; 706 interviews were conducted Monday, September 21 and Tuesday September 22, following the release of the videotape. For results based the pre-videotape wave, one can say with 95% confidence that the error attributable to sampling and other random effects is plus of minus 5%. For results based the post-videotape wave, one can say with 95% confidence that the error attributable to sampling and other random effects is plus of minus 4.5%.
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.