Monday, July 21, 2014 12:01 am
How the AP-NORC Center poll was conducted
It is based on landline and cellular telephone interviews with a nationally representative random sample of 1,002 adults. Interviews included 595 respondents on landline telephones and 407 on cellphones.
Digits in the phone numbers dialed were generated randomly to reach households with unlisted and listed landline and cellphone numbers.
Interviews were conducted in both English and Spanish.
As is done routinely in surveys, results were weighted, or adjusted, to ensure that responses accurately reflect the population's makeup by factors such as age, sex, education, race/ethnicity and region. In addition, the weighting took into account patterns of phone use — landline only, cellphone only and both.
No more than 1 time in 20 should chance variations in the sample cause the results to vary by more than plus or minus 4.0 percentage points from the answers that would be obtained if all adults in the U.S. were polled. The margin of sampling error is larger for subgroups.
There are other sources of potential error in polls, including the wording and order of questions.
The questions and results are available at http://www.apnorc.org.