The survey results are based on telephone interviews conducted under the direction of Princeton Survey Research Associates. The results presented here are from two surveys. One was among a nationwide sample of 1,200 adults, 18 years of age or older, during the period January 14-18, 1998. For results based on the total sample, one can say with 95% confidence that the error attributable to sampling and other random effects is plus or minus 3 percentage points. The second survey was among a nationwide sample of 1,002 adults, 18 years of age or older, during the period October 29-November 9, 1997. For results based on the total sample, the sampling error for this survey also is plus or minus 3 percentage points.
In addition to sampling error, one should bear it mind that question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of opinion polls.