Gallup World Poll

Methodology

To assure the Gallup World Poll survey data is representative of 95% of the world's adult population, two primary methodological designs are employed:

A Random-Digit-Dial (RDD) telephone survey design is used in countries where 80% or more of the population has landline phones. This situation is typical in the United States, Canada, Western Europe, Japan, Australia, etc.

In the developing world, including much of Latin America, the former Soviet Union countries, nearly all of Asia, the Middle East, and Africa, an area frame design is used for face-to-face interviewing.

The following are key aspects of the overall Gallup World Poll survey philosophy:

The sample represents all parts of each country*, including all rural areas. Countries are reviewed on a case-by-case basis when part of a country cannot be included in the sample design. The review determines whether the survey should be carried out.

The target population includes all individuals aged 15 and older.

Face-to-face interviews are approximately one hour in length. Telephone interviews are considerably shorter, about 30 minutes in length.

There is a standard set of questions used around the world.

In the parts of the world where face-to-face surveys are conducted, the questionnaire includes questions tailored to each region. For example, the questions used in heavily indebted poor countries are tailored toward providing information about progress on the Millennium Development Goals.

The questionnaire is translated** into the major languages of each country.

Interviewing supervisors and interviewers are trained, not only on the questionnaire, but also on the execution of field procedures. This interviewing training usually takes place in a central location.

Quality control procedures are used to validate that correct samples are selected and that the correct person is randomly selected in each household. Random respondent selection uses either the latest birthday method or the Kish grid.

^{*Three exceptions exist: Areas that threaten the safety of interviewing staff are excluded, as are scarcely populated islands in some countries, and areas that can be reached only by foot or by animal, with the exception of China.}

^{**The translation process includes two independent translations and back translations; survey personnel adjudicate the differences.}

Contact Us

Acquire the power to understand and act on what the world is thinking. For more information, please e-mail worldpollpartners@gallup.com or call 202.715.3030 (Washington, D.C.) or +44 (0) 20 7950 4400 (London).

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