Interviews for the base sample of 999 American adults age 18 and older were conducted by telephone between October 12 and 21, 1998. Interviews for an additional oversample of 331 black Americans were conducted by telephone between October 12 and 21, and October 31 and November 1, 1998. The oversample of black respondents, which resulted in a total of 400 completed interviews among African- Americans, was carried out to increase the reliability of the results obtained within this subgroup.

The margin of sampling error for the overall survey is plus or minus 3 percentage points. The margin is slightly higher among the various subgroups.