How the AP-GfK poll on the 2016 candidates was conducted
The Associated Press-GfK poll on the 2016 presidential candidates was conducted by GfK Public Affairs and Corporate Communications Dec. 3-7. It is based on online interviews of 1,007 adults, including 333 Republican and Republican leaning registered voters and 372 Democratic and Democratic leaning registered voters, who are members of GfK’s nationally representative KnowledgePanel.
The original sample was drawn from respondents recruited by phone or mail survey methods. GfK provides Internet access to participants who don’t already have it. With a probability basis and coverage of people who otherwise couldn’t access the Internet, online surveys using KnowledgePanel are nationally representative.
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, race, education and phone use.
No more than 1 time in 20 should chance variations in the sample cause the results to vary by more than plus or minus 3.4 percentage points from the answers that would be obtained if all adults in the U.S. were polled. For Republican registered voters, the margin of error is plus or minus 5.9 percentage points. For Democratic registered voters, it is plus or minus 5.6 percentage points.
There are other sources of potential error in polls, including the wording and order of questions.
The poll had a cooperation rate of 45 percent.
The questions and results are available at http://www.ap-gfkpoll.com