Survey Methods

The way polling questions are asked can influence people's answers. Survey experiments are one way to measure the degree to which different questions elicit different answers.

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.

Pew Research Center uses benchmarking questions to ensure our surveys are accurate. Learn why and how we use these questions.

On election night 2018, besides the exit polls there will be an additional source of data on who voted and why, developed by The Associated Press, Fox News and NORC at the University of Chicago and based on a very different methodology. That means that depending on where you go for election news, you may get a somewhat different portrait of this year's electorate.

Given the wide range of people we speak to for our polls – and the issues we ask them about – it’s important to be as clear as possible about exactly who says what. In research circles, this practice is sometimes called “defining the universe."

A new telephone survey experiment finds that an opinion poll drawn from a commercial voter file produces results similar to those from a sample based on random-digit dialing.

In the wake of Donald Trump’s 2016 election victory, an overwhelming majority of those who said they had voted for him had “warm” feelings for him.

Many online surveys are conducted using “nonprobability” or “opt-in” samples, which are generally easier and cheaper to conduct. In our latest Methods 101 video, we explore some of the features of nonprobability surveys and how they differ from traditional probability-based polls.

Our latest Methods 101 video explores some of the ways these surveys differ from traditional probability-based polls.

For many people, “majority” is a word so common that they rarely have to think twice about what it means. But it’s a different matter for polling organizations like Pew Research Center. At the Center, writers cannot label a survey finding a “majority” unless it meets specific criteria.