Feature

Test your knowledge of public opinion polling by taking our 10-question quiz.

We explain the basics of machine learning – using computer programs to identify patterns in data – and how it allows researchers at the Center to analyze data on a large scale.

Polling in different parts of the world can be very challenging, because what works in one country may not work in a different country.

Detailed information on Pew Research Center international survey meethodology, such as mode of interview, sampling design, margin of error, and design effect, for each country we survey, organized by survey, country and year.

The second video in Pew Research Center's Methods 101 series helps explain question wording – a concept at the center of sound public opinion survey research – and why it’s important.

The first video in Pew Research Center’s Methods 101 series helps explain random sampling – a concept that lies at the heart of all probability-based survey research – and why it’s important.