The Associated Press-GfK Poll in Turkey, on attitudes and opinions of Turks, was conducted by GfK Roper Public Affairs & Corporate Communications from Nov. 1 to Dec. 11, 2010. It is based on a national random sample of 1,200 Turks age 18 and older from different interviewing locations.
Forty-eight cities and districts were initially selected, with probability proportionate to size. Next, 60 urban blocks and 40 rural blocks were randomly selected from the 48.
Excluded from the block selection were remote areas without drivable roads, including some high-mountain terrain, and clusters of minority ethnic groups whose command of Turkish was limited. The lack of official statistics makes it difficult to estimate the amount of non-coverage, but it is probably somewhere between 7 and 12 percent.
In the blocks, interviewers were assigned random routes with rules to randomly select a household for the interview. Interviewers then recorded the number of adults in the household and randomly selected one adult for the interview. Interviewers revisited the home if the selected adult was not present.
Interviews were conducted in Turkish.
As is done routinely in surveys, results were weighted, or adjusted, to ensure that responses accurately reflect the population's makeup. The sample was weighted to take into account the sampling method, as well as for age, geography, sex, employment status, education and socio-economic status.
No more than one time in 20 should chance variations in the sample cause the results to vary by more than plus or minus 3.1 percentage points from the answers that would be obtained if all adults in Turkey were polled.
There are other sources of potential error in polls, including the wording and order of questions.
The questions and results for this poll are available at http://www.ap-gfkpoll.com.